Repository: microsoft/rego-cpp (language: python)

Issue:
Failed test for main
The following test fails on `main`:

```
 ./rego_trieste test -f --seed 3109230158
```

Uncovered in my PR (https://github.com/microsoft/rego-cpp/actions/runs/6131481980/job/16641498709?pr=70#step:5:64), but this failed on main when I tried it.


Discussion / hints:
This looks like a related failure:
```
./rego_trieste "test" "-f" --seed 3166257874
```

This is from a different PR (https://github.com/microsoft/rego-cpp/actions/runs/6139291462/job/16657047458?pr=73#step:5:63)

1355977544

Fix patch:
diff --git a/CHANGELOG b/CHANGELOG
index dda73a4a..5898ded5 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,5 +1,23 @@
 # Changelog
 
+## 2023-09-12 - Version 0.3.5
+Adding C++ documentation.
+
+**New Features**
+- The C++ API is now documented using Doxygen. The documentation can be found
+  [here](https://microsoft.github.io/regocpp/).
+- Logging levels have been added and can be set via the API (instead of just
+  binary enabled/disabled)
+
+**Breaking changes**
+- _C API_: The `regoSetLoggingEnabled` function has been replaced with
+  `regoSetLoggingLevel`. This is also reflected in the C++ and Rust APIs.h
+- _C API_: The `regoSetExecutablePath` function has been removed due to the
+  `Interpreter::executable()` property being removed from the C++ API.
+- The `to_json` method flag `rego_set` has been changed to `set_as_array` and
+  the order of its flag inverted (it is now `false` by default).
+
+
 ## 2023-09-10 - Version 0.3.4
 Adding a Rust wrapper.
 
diff --git a/CMakeLists.txt b/CMakeLists.txt
index e7258f75..8bac599f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -64,6 +64,7 @@ set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
 option(REGOCPP_BUILD_TOOLS "Specifies whether to build the command line tools" OFF)
 option(REGOCPP_BUILD_TESTS "Specifies whether to build the tests" OFF)
+option(REGOCPP_BUILD_DOCS "Specifies whether to build the documentation" OFF)
 option(REGOCPP_OPA_TESTS "Specifies whether to load and run the OPA built-ins tests" OFF)
 option(REGOCPP_SPECULATIVE_LOAD_HARDENING "Specifies whether to enable speculative load hardening, only supported with Clang" OFF)
 option(REGOCPP_COPY_EXAMPLES "Specifies whether to copy the examples to the install directory" OFF)
@@ -72,8 +73,8 @@ option(REGOCPP_COPY_EXAMPLES "Specifies whether to copy the examples to the inst
 
 FetchContent_Declare(
   trieste
-  GIT_REPOSITORY https://github.com/matajoh/trieste
-  GIT_TAG        7bf503b81db295ddbddd8d0010f5d820057ec8a8
+  GIT_REPOSITORY https://github.com/microsoft/trieste
+  GIT_TAG        5f75cf7aeb74890066ff249a82fa14dc031a9642
 )
 
 set(CMAKE_POLICY_DEFAULT_CMP0077 NEW) 
@@ -107,9 +108,11 @@ if(CLANG_FORMAT_NOT_FOUND)
 else()
   file(GLOB_RECURSE ALL_SOURCE_FILES CONFIGURE_DEPENDS
         src/*.cc
+        src/*.hh
         src/passes/*.cc
         src/*.h
         include/rego/*.h
+        include/rego/*.hh
         tools/*.cc
         tests/*.cc
         tests/*.h
@@ -152,6 +155,11 @@ if(REGOCPP_BUILD_TOOLS)
   add_subdirectory(tools)
 endif()
 
+if(REGOCPP_BUILD_DOCS)
+  find_package( Doxygen REQUIRED )
+  add_subdirectory( doc )
+endif()
+
 # -------------------- Install ------------------------------------
 
 set(INSTALL_CONFIGDIR cmake)
diff --git a/README.md b/README.md
index 980ed1df..8aa5ff9d 100644
--- a/README.md
+++ b/README.md
@@ -47,9 +47,9 @@ You can then build and run the tests using:
     cmake --build . --config Release --target INSTALL
     ctest -C Release
 
-### Using the Interpreter
+### Using the `rego` CLI
 
-The interpreter will be located at `build/dist/bin/rego`. Here are
+The interpreter tool will be located at `build/dist/bin/rego`. Here are
 some example commands using the provided example files and run from the suggested
 `dist` install directory:
 
@@ -72,6 +72,11 @@ You can run the test driver from the same directory:
 
     ./bin/rego_test tests/regocpp.yaml
 
+### Using the `rego` Library
+
+See the [examples](examples/README.md) directory for examples of how to use the
+library from different langauages.
+
 ## Language Support
 
 At present we support v0.55.0 of Rego as defined by OPA, with the following grammar:
diff --git a/VERSION b/VERSION
index 448a0fa1..09e91570 100644
--- a/VERSION
+++ b/VERSION
@@ -1,1 +1,1 @@
-0.3.4
\ No newline at end of file
+0.3.5
\ No newline at end of file
diff --git a/doc/CMakeLists.txt b/doc/CMakeLists.txt
new file mode 100644
index 00000000..df809f96
--- /dev/null
+++ b/doc/CMakeLists.txt
@@ -0,0 +1,13 @@
+# build the documentation from the C++ comments
+configure_file( 
+  Doxyfile.in 
+  ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile @ONLY 
+)
+
+add_custom_target( regocpp_doc
+  ALL
+  ${DOXYGEN_EXECUTABLE} 
+  ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile
+  WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
+  COMMENT "Generating API documentation with Doxygen" VERBATIM
+)
diff --git a/doc/Doxyfile.in b/doc/Doxyfile.in
new file mode 100644
index 00000000..4f151653
--- /dev/null
+++ b/doc/Doxyfile.in
@@ -0,0 +1,2613 @@
+# Doxyfile 1.9.1
+
+# This file describes the settings to be used by the documentation system
+# doxygen (www.doxygen.org) for a project.
+#
+# All text after a double hash (##) is considered a comment and is placed in
+# front of the TAG it is preceding.
+#
+# All text after a single hash (#) is considered a comment and will be ignored.
+# The format is:
+# TAG = value [value, ...]
+# For lists, items can also be appended using:
+# TAG += value [value, ...]
+# Values that contain spaces should be placed between quotes (\" \").
+
+#---------------------------------------------------------------------------
+# Project related configuration options
+#---------------------------------------------------------------------------
+
+# This tag specifies the encoding used for all characters in the configuration
+# file that follow. The default is UTF-8 which is also the encoding used for all
+# text before the first occurrence of this tag. Doxygen uses libiconv (or the
+# iconv built into libc) for the transcoding. See
+# https://www.gnu.org/software/libiconv/ for the list of possible encodings.
+# The default value is: UTF-8.
+
+DOXYFILE_ENCODING      = UTF-8
+
+# The PROJECT_NAME tag is a single word (or a sequence of words surrounded by
+# double-quotes, unless you are using Doxywizard) that should identify the
+# project for which the documentation is generated. This name is used in the
+# title of most generated pages and in a few other places.
+# The default value is: My Project.
+
+PROJECT_NAME           = "rego-cpp"
+
+# The PROJECT_NUMBER tag can be used to enter a project or revision number. This
+# could be handy for archiving the generated documentation or if some version
+# control system is used.
+
+PROJECT_NUMBER         = @REGOCPP_VERSION@
+
+# Using the PROJECT_BRIEF tag one can provide an optional one line description
+# for a project that appears at the top of each page and should give viewer a
+# quick idea about the purpose of the project. Keep the description short.
+
+PROJECT_BRIEF          = A C++ implementation of the Rego language and runtime
+
+# With the PROJECT_LOGO tag one can specify a logo or an icon that is included
+# in the documentation. The maximum height of the logo should not exceed 55
+# pixels and the maximum width should not exceed 200 pixels. Doxygen will copy
+# the logo to the output directory.
+
+PROJECT_LOGO           =
+
+# The OUTPUT_DIRECTORY tag is used to specify the (relative or absolute) path
+# into which the generated documentation will be written. If a relative path is
+# entered, it will be relative to the location where doxygen was started. If
+# left blank the current directory will be used.
+
+OUTPUT_DIRECTORY       = doc
+
+# If the CREATE_SUBDIRS tag is set to YES then doxygen will create 4096 sub-
+# directories (in 2 levels) under the output directory of each output format and
+# will distribute the generated files over these directories. Enabling this
+# option can be useful when feeding doxygen a huge amount of source files, where
+# putting all generated files in the same directory would otherwise causes
+# performance problems for the file system.
+# The default value is: NO.
+
+CREATE_SUBDIRS         = NO
+
+# If the ALLOW_UNICODE_NAMES tag is set to YES, doxygen will allow non-ASCII
+# characters to appear in the names of generated files. If set to NO, non-ASCII
+# characters will be escaped, for example _xE3_x81_x84 will be used for Unicode
+# U+3044.
+# The default value is: NO.
+
+ALLOW_UNICODE_NAMES    = NO
+
+# The OUTPUT_LANGUAGE tag is used to specify the language in which all
+# documentation generated by doxygen is written. Doxygen will use this
+# information to generate all constant output in the proper language.
+# Possible values are: Afrikaans, Arabic, Armenian, Brazilian, Catalan, Chinese,
+# Chinese-Traditional, Croatian, Czech, Danish, Dutch, English (United States),
+# Esperanto, Farsi (Persian), Finnish, French, German, Greek, Hungarian,
+# Indonesian, Italian, Japanese, Japanese-en (Japanese with English messages),
+# Korean, Korean-en (Korean with English messages), Latvian, Lithuanian,
+# Macedonian, Norwegian, Persian (Farsi), Polish, Portuguese, Romanian, Russian,
+# Serbian, Serbian-Cyrillic, Slovak, Slovene, Spanish, Swedish, Turkish,
+# Ukrainian and Vietnamese.
+# The default value is: English.
+
+OUTPUT_LANGUAGE        = English
+
+# If the BRIEF_MEMBER_DESC tag is set to YES, doxygen will include brief member
+# descriptions after the members that are listed in the file and class
+# documentation (similar to Javadoc). Set to NO to disable this.
+# The default value is: YES.
+
+BRIEF_MEMBER_DESC      = YES
+
+# If the REPEAT_BRIEF tag is set to YES, doxygen will prepend the brief
+# description of a member or function before the detailed description
+#
+# Note: If both HIDE_UNDOC_MEMBERS and BRIEF_MEMBER_DESC are set to NO, the
+# brief descriptions will be completely suppressed.
+# The default value is: YES.
+
+REPEAT_BRIEF           = YES
+
+# This tag implements a quasi-intelligent brief description abbreviator that is
+# used to form the text in various listings. Each string in this list, if found
+# as the leading text of the brief description, will be stripped from the text
+# and the result, after processing the whole list, is used as the annotated
+# text. Otherwise, the brief description is used as-is. If left blank, the
+# following values are used ($name is automatically replaced with the name of
+# the entity):The $name class, The $name widget, The $name file, is, provides,
+# specifies, contains, represents, a, an and the.
+
+ABBREVIATE_BRIEF       = "The $name class" \
+                         "The $name widget" \
+                         "The $name file" \
+                         is \
+                         provides \
+                         specifies \
+                         contains \
+                         represents \
+                         a \
+                         an \
+                         the
+
+# If the ALWAYS_DETAILED_SEC and REPEAT_BRIEF tags are both set to YES then
+# doxygen will generate a detailed section even if there is only a brief
+# description.
+# The default value is: NO.
+
+ALWAYS_DETAILED_SEC    = NO
+
+# If the INLINE_INHERITED_MEMB tag is set to YES, doxygen will show all
+# inherited members of a class in the documentation of that class as if those
+# members were ordinary class members. Constructors, destructors and assignment
+# operators of the base classes will not be shown.
+# The default value is: NO.
+
+INLINE_INHERITED_MEMB  = NO
+
+# If the FULL_PATH_NAMES tag is set to YES, doxygen will prepend the full path
+# before files name in the file list and in the header files. If set to NO the
+# shortest path that makes the file name unique will be used
+# The default value is: YES.
+
+FULL_PATH_NAMES        = YES
+
+# The STRIP_FROM_PATH tag can be used to strip a user-defined part of the path.
+# Stripping is only done if one of the specified strings matches the left-hand
+# part of the path. The tag can be used to show relative paths in the file list.
+# If left blank the directory from which doxygen is run is used as the path to
+# strip.
+#
+# Note that you can specify absolute paths here, but also relative paths, which
+# will be relative from the directory where doxygen is started.
+# This tag requires that the tag FULL_PATH_NAMES is set to YES.
+
+STRIP_FROM_PATH        = @CMAKE_SOURCE_DIR@
+
+# The STRIP_FROM_INC_PATH tag can be used to strip a user-defined part of the
+# path mentioned in the documentation of a class, which tells the reader which
+# header file to include in order to use a class. If left blank only the name of
+# the header file containing the class definition is used. Otherwise one should
+# specify the list of include paths that are normally passed to the compiler
+# using the -I flag.
+
+STRIP_FROM_INC_PATH    =
+
+# If the SHORT_NAMES tag is set to YES, doxygen will generate much shorter (but
+# less readable) file names. This can be useful is your file systems doesn't
+# support long names like on DOS, Mac, or CD-ROM.
+# The default value is: NO.
+
+SHORT_NAMES            = NO
+
+# If the JAVADOC_AUTOBRIEF tag is set to YES then doxygen will interpret the
+# first line (until the first dot) of a Javadoc-style comment as the brief
+# description. If set to NO, the Javadoc-style will behave just like regular Qt-
+# style comments (thus requiring an explicit @brief command for a brief
+# description.)
+# The default value is: NO.
+
+JAVADOC_AUTOBRIEF      = NO
+
+# If the JAVADOC_BANNER tag is set to YES then doxygen will interpret a line
+# such as
+# /***************
+# as being the beginning of a Javadoc-style comment "banner". If set to NO, the
+# Javadoc-style will behave just like regular comments and it will not be
+# interpreted by doxygen.
+# The default value is: NO.
+
+JAVADOC_BANNER         = NO
+
+# If the QT_AUTOBRIEF tag is set to YES then doxygen will interpret the first
+# line (until the first dot) of a Qt-style comment as the brief description. If
+# set to NO, the Qt-style will behave just like regular Qt-style comments (thus
+# requiring an explicit \brief command for a brief description.)
+# The default value is: NO.
+
+QT_AUTOBRIEF           = NO
+
+# The MULTILINE_CPP_IS_BRIEF tag can be set to YES to make doxygen treat a
+# multi-line C++ special comment block (i.e. a block of //! or /// comments) as
+# a brief description. This used to be the default behavior. The new default is
+# to treat a multi-line C++ comment block as a detailed description. Set this
+# tag to YES if you prefer the old behavior instead.
+#
+# Note that setting this tag to YES also means that rational rose comments are
+# not recognized any more.
+# The default value is: NO.
+
+MULTILINE_CPP_IS_BRIEF = NO
+
+# By default Python docstrings are displayed as preformatted text and doxygen's
+# special commands cannot be used. By setting PYTHON_DOCSTRING to NO the
+# doxygen's special commands can be used and the contents of the docstring
+# documentation blocks is shown as doxygen documentation.
+# The default value is: YES.
+
+PYTHON_DOCSTRING       = YES
+
+# If the INHERIT_DOCS tag is set to YES then an undocumented member inherits the
+# documentation from any documented member that it re-implements.
+# The default value is: YES.
+
+INHERIT_DOCS           = YES
+
+# If the SEPARATE_MEMBER_PAGES tag is set to YES then doxygen will produce a new
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+# of the file/class/namespace that contains it.
+# The default value is: NO.
+
+SEPARATE_MEMBER_PAGES  = NO
+
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+# uses this value to replace tabs by spaces in code fragments.
+# Minimum value: 1, maximum value: 16, default value: 4.
+
+TAB_SIZE               = 4
+
+# This tag can be used to specify a number of aliases that act as commands in
+# the documentation. An alias has the form:
+# name=value
+# For example adding
+# "sideeffect=@par Side Effects:\n"
+# will allow you to put the command \sideeffect (or @sideeffect) in the
+# documentation, which will result in a user-defined paragraph with heading
+# "Side Effects:". You can put \n's in the value part of an alias to insert
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+# When you need a literal { or } or , in the value part of an alias you have to
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+# commands \{ and \} for these it is advised to use the version @{ and @} or use
+# a double escape (\\{ and \\})
+
+ALIASES                =
+
+# Set the OPTIMIZE_OUTPUT_FOR_C tag to YES if your project consists of C sources
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+# members will be omitted, etc.
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+
+OPTIMIZE_OUTPUT_FOR_C  = NO
+
+# Set the OPTIMIZE_OUTPUT_JAVA tag to YES if your project consists of Java or
+# Python sources only. Doxygen will then generate output that is more tailored
+# for that language. For instance, namespaces will be presented as packages,
+# qualified scopes will look different, etc.
+# The default value is: NO.
+
+OPTIMIZE_OUTPUT_JAVA   = NO
+
+# Set the OPTIMIZE_FOR_FORTRAN tag to YES if your project consists of Fortran
+# sources. Doxygen will then generate output that is tailored for Fortran.
+# The default value is: NO.
+
+OPTIMIZE_FOR_FORTRAN   = NO
+
+# Set the OPTIMIZE_OUTPUT_VHDL tag to YES if your project consists of VHDL
+# sources. Doxygen will then generate output that is tailored for VHDL.
+# The default value is: NO.
+
+OPTIMIZE_OUTPUT_VHDL   = NO
+
+# Set the OPTIMIZE_OUTPUT_SLICE tag to YES if your project consists of Slice
+# sources only. Doxygen will then generate output that is more tailored for that
+# language. For instance, namespaces will be presented as modules, types will be
+# separated into more groups, etc.
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+
+OPTIMIZE_OUTPUT_SLICE  = NO
+
+# Doxygen selects the parser to use depending on the extension of the files it
+# parses. With this tag you can assign which parser to use for a given
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+# Csharp (C#), C, C++, D, PHP, md (Markdown), Objective-C, Python, Slice, VHDL,
+# Fortran (fixed format Fortran: FortranFixed, free formatted Fortran:
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+# tries to guess whether the code is fixed or free formatted code, this is the
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+# use: inc=Fortran f=C.
+#
+# Note: For files without extension you can use no_extension as a placeholder.
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+# Note see also the list of default file extension mappings.
+
+EXTENSION_MAPPING      =
+
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+# mix doxygen, HTML, and XML commands with Markdown formatting. Disable only in
+# case of backward compatibilities issues.
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+
+MARKDOWN_SUPPORT       = YES
+
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+
+TOC_INCLUDE_HEADINGS   = 5
+
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+
+AUTOLINK_SUPPORT       = YES
+
+# If you use STL classes (i.e. std::string, std::vector, etc.) but do not want
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+# versus func(std::string) {}). This also make the inheritance and collaboration
+# diagrams that involve STL classes more complete and accurate.
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+
+BUILTIN_STL_SUPPORT    = NO
+
+# If you use Microsoft's C++/CLI language, you should set this option to YES to
+# enable parsing support.
+# The default value is: NO.
+
+CPP_CLI_SUPPORT        = NO
+
+# Set the SIP_SUPPORT tag to YES if your project consists of sip (see:
+# https://www.riverbankcomputing.com/software/sip/intro) sources only. Doxygen
+# will parse them like normal C++ but will assume all classes use public instead
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+
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+
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+
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+
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+
+GROUP_NESTED_COMPOUNDS = NO
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+
+SUBGROUPING            = YES
+
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+#
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+
+INLINE_GROUPED_CLASSES = NO
+
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+
+INLINE_SIMPLE_STRUCTS  = NO
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+
+TYPEDEF_HIDES_STRUCT   = NO
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+# symbols. At the end of a run doxygen will report the cache usage and suggest
+# the optimal cache size from a speed point of view.
+# Minimum value: 0, maximum value: 9, default value: 0.
+
+LOOKUP_CACHE_SIZE      = 0
+
+# The NUM_PROC_THREADS specifies the number threads doxygen is allowed to use
+# during processing. When set to 0 doxygen will based this on the number of
+# cores available in the system. You can set it explicitly to a value larger
+# than 0 to get more control over the balance between CPU load and processing
+# speed. At this moment only the input processing can be done using multiple
+# threads. Since this is still an experimental feature the default is set to 1,
+# which efficively disables parallel processing. Please report any issues you
+# encounter. Generating dot graphs in parallel is controlled by the
+# DOT_NUM_THREADS setting.
+# Minimum value: 0, maximum value: 32, default value: 1.
+
+NUM_PROC_THREADS       = 1
+
+#---------------------------------------------------------------------------
+# Build related configuration options
+#---------------------------------------------------------------------------
+
+# If the EXTRACT_ALL tag is set to YES, doxygen will assume all entities in
+# documentation are documented, even if no documentation was available. Private
+# class members and static file members will be hidden unless the
+# EXTRACT_PRIVATE respectively EXTRACT_STATIC tags are set to YES.
+# Note: This will also disable the warnings about undocumented members that are
+# normally produced when WARNINGS is set to YES.
+# The default value is: NO.
+
+EXTRACT_ALL            = NO
+
+# If the EXTRACT_PRIVATE tag is set to YES, all private members of a class will
+# be included in the documentation.
+# The default value is: NO.
+
+EXTRACT_PRIVATE        = NO
+
+# If the EXTRACT_PRIV_VIRTUAL tag is set to YES, documented private virtual
+# methods of a class will be included in the documentation.
+# The default value is: NO.
+
+EXTRACT_PRIV_VIRTUAL   = NO
+
+# If the EXTRACT_PACKAGE tag is set to YES, all members with package or internal
+# scope will be included in the documentation.
+# The default value is: NO.
+
+EXTRACT_PACKAGE        = NO
+
+# If the EXTRACT_STATIC tag is set to YES, all static members of a file will be
+# included in the documentation.
+# The default value is: NO.
+
+EXTRACT_STATIC         = NO
+
+# If the EXTRACT_LOCAL_CLASSES tag is set to YES, classes (and structs) defined
+# locally in source files will be included in the documentation. If set to NO,
+# only classes defined in header files are included. Does not have any effect
+# for Java sources.
+# The default value is: YES.
+
+EXTRACT_LOCAL_CLASSES  = YES
+
+# This flag is only useful for Objective-C code. If set to YES, local methods,
+# which are defined in the implementation section but not in the interface are
+# included in the documentation. If set to NO, only methods in the interface are
+# included.
+# The default value is: NO.
+
+EXTRACT_LOCAL_METHODS  = NO
+
+# If this flag is set to YES, the members of anonymous namespaces will be
+# extracted and appear in the documentation as a namespace called
+# 'anonymous_namespace{file}', where file will be replaced with the base name of
+# the file that contains the anonymous namespace. By default anonymous namespace
+# are hidden.
+# The default value is: NO.
+
+EXTRACT_ANON_NSPACES   = NO
+
+# If this flag is set to YES, the name of an unnamed parameter in a declaration
+# will be determined by the corresponding definition. By default unnamed
+# parameters remain unnamed in the output.
+# The default value is: YES.
+
+RESOLVE_UNNAMED_PARAMS = YES
+
+# If the HIDE_UNDOC_MEMBERS tag is set to YES, doxygen will hide all
+# undocumented members inside documented classes or files. If set to NO these
+# members will be included in the various overviews, but no documentation
+# section is generated. This option has no effect if EXTRACT_ALL is enabled.
+# The default value is: NO.
+
+HIDE_UNDOC_MEMBERS     = NO
+
+# If the HIDE_UNDOC_CLASSES tag is set to YES, doxygen will hide all
+# undocumented classes that are normally visible in the class hierarchy. If set
+# to NO, these classes will be included in the various overviews. This option
+# has no effect if EXTRACT_ALL is enabled.
+# The default value is: NO.
+
+HIDE_UNDOC_CLASSES     = NO
+
+# If the HIDE_FRIEND_COMPOUNDS tag is set to YES, doxygen will hide all friend
+# declarations. If set to NO, these declarations will be included in the
+# documentation.
+# The default value is: NO.
+
+HIDE_FRIEND_COMPOUNDS  = NO
+
+# If the HIDE_IN_BODY_DOCS tag is set to YES, doxygen will hide any
+# documentation blocks found inside the body of a function. If set to NO, these
+# blocks will be appended to the function's detailed documentation block.
+# The default value is: NO.
+
+HIDE_IN_BODY_DOCS      = NO
+
+# The INTERNAL_DOCS tag determines if documentation that is typed after a
+# \internal command is included. If the tag is set to NO then the documentation
+# will be excluded. Set it to YES to include the internal documentation.
+# The default value is: NO.
+
+INTERNAL_DOCS          = NO
+
+# With the correct setting of option CASE_SENSE_NAMES doxygen will better be
+# able to match the capabilities of the underlying filesystem. In case the
+# filesystem is case sensitive (i.e. it supports files in the same directory
+# whose names only differ in casing), the option must be set to YES to properly
+# deal with such files in case they appear in the input. For filesystems that
+# are not case sensitive the option should be be set to NO to properly deal with
+# output files written for symbols that only differ in casing, such as for two
+# classes, one named CLASS and the other named Class, and to also support
+# references to files without having to specify the exact matching casing. On
+# Windows (including Cygwin) and MacOS, users should typically set this option
+# to NO, whereas on Linux or other Unix flavors it should typically be set to
+# YES.
+# The default value is: system dependent.
+
+CASE_SENSE_NAMES       = YES
+
+# If the HIDE_SCOPE_NAMES tag is set to NO then doxygen will show members with
+# their full class and namespace scopes in the documentation. If set to YES, the
+# scope will be hidden.
+# The default value is: NO.
+
+HIDE_SCOPE_NAMES       = NO
+
+# If the HIDE_COMPOUND_REFERENCE tag is set to NO (default) then doxygen will
+# append additional text to a page's title, such as Class Reference. If set to
+# YES the compound reference will be hidden.
+# The default value is: NO.
+
+HIDE_COMPOUND_REFERENCE= NO
+
+# If the SHOW_INCLUDE_FILES tag is set to YES then doxygen will put a list of
+# the files that are included by a file in the documentation of that file.
+# The default value is: YES.
+
+SHOW_INCLUDE_FILES     = YES
+
+# If the SHOW_GROUPED_MEMB_INC tag is set to YES then Doxygen will add for each
+# grouped member an include statement to the documentation, telling the reader
+# which file to include in order to use the member.
+# The default value is: NO.
+
+SHOW_GROUPED_MEMB_INC  = NO
+
+# If the FORCE_LOCAL_INCLUDES tag is set to YES then doxygen will list include
+# files with double quotes in the documentation rather than with sharp brackets.
+# The default value is: NO.
+
+FORCE_LOCAL_INCLUDES   = NO
+
+# If the INLINE_INFO tag is set to YES then a tag [inline] is inserted in the
+# documentation for inline members.
+# The default value is: YES.
+
+INLINE_INFO            = YES
+
+# If the SORT_MEMBER_DOCS tag is set to YES then doxygen will sort the
+# (detailed) documentation of file and class members alphabetically by member
+# name. If set to NO, the members will appear in declaration order.
+# The default value is: YES.
+
+SORT_MEMBER_DOCS       = YES
+
+# If the SORT_BRIEF_DOCS tag is set to YES then doxygen will sort the brief
+# descriptions of file, namespace and class members alphabetically by member
+# name. If set to NO, the members will appear in declaration order. Note that
+# this will also influence the order of the classes in the class list.
+# The default value is: NO.
+
+SORT_BRIEF_DOCS        = NO
+
+# If the SORT_MEMBERS_CTORS_1ST tag is set to YES then doxygen will sort the
+# (brief and detailed) documentation of class members so that constructors and
+# destructors are listed first. If set to NO the constructors will appear in the
+# respective orders defined by SORT_BRIEF_DOCS and SORT_MEMBER_DOCS.
+# Note: If SORT_BRIEF_DOCS is set to NO this option is ignored for sorting brief
+# member documentation.
+# Note: If SORT_MEMBER_DOCS is set to NO this option is ignored for sorting
+# detailed member documentation.
+# The default value is: NO.
+
+SORT_MEMBERS_CTORS_1ST = NO
+
+# If the SORT_GROUP_NAMES tag is set to YES then doxygen will sort the hierarchy
+# of group names into alphabetical order. If set to NO the group names will
+# appear in their defined order.
+# The default value is: NO.
+
+SORT_GROUP_NAMES       = NO
+
+# If the SORT_BY_SCOPE_NAME tag is set to YES, the class list will be sorted by
+# fully-qualified names, including namespaces. If set to NO, the class list will
+# be sorted only by class name, not including the namespace part.
+# Note: This option is not very useful if HIDE_SCOPE_NAMES is set to YES.
+# Note: This option applies only to the class list, not to the alphabetical
+# list.
+# The default value is: NO.
+
+SORT_BY_SCOPE_NAME     = NO
+
+# If the STRICT_PROTO_MATCHING option is enabled and doxygen fails to do proper
+# type resolution of all parameters of a function it will reject a match between
+# the prototype and the implementation of a member function even if there is
+# only one candidate or it is obvious which candidate to choose by doing a
+# simple string match. By disabling STRICT_PROTO_MATCHING doxygen will still
+# accept a match between prototype and implementation in such cases.
+# The default value is: NO.
+
+STRICT_PROTO_MATCHING  = NO
+
+# The GENERATE_TODOLIST tag can be used to enable (YES) or disable (NO) the todo
+# list. This list is created by putting \todo commands in the documentation.
+# The default value is: YES.
+
+GENERATE_TODOLIST      = YES
+
+# The GENERATE_TESTLIST tag can be used to enable (YES) or disable (NO) the test
+# list. This list is created by putting \test commands in the documentation.
+# The default value is: YES.
+
+GENERATE_TESTLIST      = YES
+
+# The GENERATE_BUGLIST tag can be used to enable (YES) or disable (NO) the bug
+# list. This list is created by putting \bug commands in the documentation.
+# The default value is: YES.
+
+GENERATE_BUGLIST       = YES
+
+# The GENERATE_DEPRECATEDLIST tag can be used to enable (YES) or disable (NO)
+# the deprecated list. This list is created by putting \deprecated commands in
+# the documentation.
+# The default value is: YES.
+
+GENERATE_DEPRECATEDLIST= YES
+
+# The ENABLED_SECTIONS tag can be used to enable conditional documentation
+# sections, marked by \if <section_label> ... \endif and \cond <section_label>
+# ... \endcond blocks.
+
+ENABLED_SECTIONS       =
+
+# The MAX_INITIALIZER_LINES tag determines the maximum number of lines that the
+# initial value of a variable or macro / define can have for it to appear in the
+# documentation. If the initializer consists of more lines than specified here
+# it will be hidden. Use a value of 0 to hide initializers completely. The
+# appearance of the value of individual variables and macros / defines can be
+# controlled using \showinitializer or \hideinitializer command in the
+# documentation regardless of this setting.
+# Minimum value: 0, maximum value: 10000, default value: 30.
+
+MAX_INITIALIZER_LINES  = 30
+
+# Set the SHOW_USED_FILES tag to NO to disable the list of files generated at
+# the bottom of the documentation of classes and structs. If set to YES, the
+# list will mention the files that were used to generate the documentation.
+# The default value is: YES.
+
+SHOW_USED_FILES        = YES
+
+# Set the SHOW_FILES tag to NO to disable the generation of the Files page. This
+# will remove the Files entry from the Quick Index and from the Folder Tree View
+# (if specified).
+# The default value is: YES.
+
+SHOW_FILES             = YES
+
+# Set the SHOW_NAMESPACES tag to NO to disable the generation of the Namespaces
+# page. This will remove the Namespaces entry from the Quick Index and from the
+# Folder Tree View (if specified).
+# The default value is: YES.
+
+SHOW_NAMESPACES        = YES
+
+# The FILE_VERSION_FILTER tag can be used to specify a program or script that
+# doxygen should invoke to get the current version for each file (typically from
+# the version control system). Doxygen will invoke the program by executing (via
+# popen()) the command command input-file, where command is the value of the
+# FILE_VERSION_FILTER tag, and input-file is the name of an input file provided
+# by doxygen. Whatever the program writes to standard output is used as the file
+# version. For an example see the documentation.
+
+FILE_VERSION_FILTER    =
+
+# The LAYOUT_FILE tag can be used to specify a layout file which will be parsed
+# by doxygen. The layout file controls the global structure of the generated
+# output files in an output format independent way. To create the layout file
+# that represents doxygen's defaults, run doxygen with the -l option. You can
+# optionally specify a file name after the option, if omitted DoxygenLayout.xml
+# will be used as the name of the layout file.
+#
+# Note that if you run doxygen from a directory containing a file called
+# DoxygenLayout.xml, doxygen will parse it automatically even if the LAYOUT_FILE
+# tag is left empty.
+
+LAYOUT_FILE            =
+
+# The CITE_BIB_FILES tag can be used to specify one or more bib files containing
+# the reference definitions. This must be a list of .bib files. The .bib
+# extension is automatically appended if omitted. This requires the bibtex tool
+# to be installed. See also https://en.wikipedia.org/wiki/BibTeX for more info.
+# For LaTeX the style of the bibliography can be controlled using
+# LATEX_BIB_STYLE. To use this feature you need bibtex and perl available in the
+# search path. See also \cite for info how to create references.
+
+CITE_BIB_FILES         =
+
+#---------------------------------------------------------------------------
+# Configuration options related to warning and progress messages
+#---------------------------------------------------------------------------
+
+# The QUIET tag can be used to turn on/off the messages that are generated to
+# standard output by doxygen. If QUIET is set to YES this implies that the
+# messages are off.
+# The default value is: NO.
+
+QUIET                  = NO
+
+# The WARNINGS tag can be used to turn on/off the warning messages that are
+# generated to standard error (stderr) by doxygen. If WARNINGS is set to YES
+# this implies that the warnings are on.
+#
+# Tip: Turn warnings on while writing the documentation.
+# The default value is: YES.
+
+WARNINGS               = YES
+
+# If the WARN_IF_UNDOCUMENTED tag is set to YES then doxygen will generate
+# warnings for undocumented members. If EXTRACT_ALL is set to YES then this flag
+# will automatically be disabled.
+# The default value is: YES.
+
+WARN_IF_UNDOCUMENTED   = YES
+
+# If the WARN_IF_DOC_ERROR tag is set to YES, doxygen will generate warnings for
+# potential errors in the documentation, such as not documenting some parameters
+# in a documented function, or documenting parameters that don't exist or using
+# markup commands wrongly.
+# The default value is: YES.
+
+WARN_IF_DOC_ERROR      = YES
+
+# This WARN_NO_PARAMDOC option can be enabled to get warnings for functions that
+# are documented, but have no documentation for their parameters or return
+# value. If set to NO, doxygen will only warn about wrong or incomplete
+# parameter documentation, but not about the absence of documentation. If
+# EXTRACT_ALL is set to YES then this flag will automatically be disabled.
+# The default value is: NO.
+
+WARN_NO_PARAMDOC       = NO
+
+# If the WARN_AS_ERROR tag is set to YES then doxygen will immediately stop when
+# a warning is encountered. If the WARN_AS_ERROR tag is set to FAIL_ON_WARNINGS
+# then doxygen will continue running as if WARN_AS_ERROR tag is set to NO, but
+# at the end of the doxygen process doxygen will return with a non-zero status.
+# Possible values are: NO, YES and FAIL_ON_WARNINGS.
+# The default value is: NO.
+
+WARN_AS_ERROR          = NO
+
+# The WARN_FORMAT tag determines the format of the warning messages that doxygen
+# can produce. The string should contain the $file, $line, and $text tags, which
+# will be replaced by the file and line number from which the warning originated
+# and the warning text. Optionally the format may contain $version, which will
+# be replaced by the version of the file (if it could be obtained via
+# FILE_VERSION_FILTER)
+# The default value is: $file:$line: $text.
+
+WARN_FORMAT            = "$file:$line: $text"
+
+# The WARN_LOGFILE tag can be used to specify a file to which warning and error
+# messages should be written. If left blank the output is written to standard
+# error (stderr).
+
+WARN_LOGFILE           =
+
+#---------------------------------------------------------------------------
+# Configuration options related to the input files
+#---------------------------------------------------------------------------
+
+# The INPUT tag is used to specify the files and/or directories that contain
+# documented source files. You may enter file names like myfile.cpp or
+# directories like /usr/src/myproject. Separate the files or directories with
+# spaces. See also FILE_PATTERNS and EXTENSION_MAPPING
+# Note: If this tag is empty the current directory is searched.
+
+INPUT                  = @CMAKE_SOURCE_DIR@/include/rego \
+                         @CMAKE_SOURCE_DIR@/README.md
+
+# This tag can be used to specify the character encoding of the source files
+# that doxygen parses. Internally doxygen uses the UTF-8 encoding. Doxygen uses
+# libiconv (or the iconv built into libc) for the transcoding. See the libiconv
+# documentation (see:
+# https://www.gnu.org/software/libiconv/) for the list of possible encodings.
+# The default value is: UTF-8.
+
+INPUT_ENCODING         = UTF-8
+
+# If the value of the INPUT tag contains directories, you can use the
+# FILE_PATTERNS tag to specify one or more wildcard patterns (like *.cpp and
+# *.h) to filter out the source-files in the directories.
+#
+# Note that for custom extensions or not directly supported extensions you also
+# need to set EXTENSION_MAPPING for the extension otherwise the files are not
+# read by doxygen.
+#
+# Note the list of default checked file patterns might differ from the list of
+# default file extension mappings.
+#
+# If left blank the following patterns are tested:*.c, *.cc, *.cxx, *.cpp,
+# *.c++, *.java, *.ii, *.ixx, *.ipp, *.i++, *.inl, *.idl, *.ddl, *.odl, *.h,
+# *.hh, *.hxx, *.hpp, *.h++, *.cs, *.d, *.php, *.php4, *.php5, *.phtml, *.inc,
+# *.m, *.markdown, *.md, *.mm, *.dox (to be provided as doxygen C comment),
+# *.py, *.pyw, *.f90, *.f95, *.f03, *.f08, *.f18, *.f, *.for, *.vhd, *.vhdl,
+# *.ucf, *.qsf and *.ice.
+
+FILE_PATTERNS          = *.c \
+                         *.cc \
+                         *.cxx \
+                         *.cpp \
+                         *.c++ \
+                         *.java \
+                         *.ii \
+                         *.ixx \
+                         *.ipp \
+                         *.i++ \
+                         *.inl \
+                         *.idl \
+                         *.ddl \
+                         *.odl \
+                         *.h \
+                         *.hh \
+                         *.hxx \
+                         *.hpp \
+                         *.h++ \
+                         *.cs \
+                         *.d \
+                         *.php \
+                         *.php4 \
+                         *.php5 \
+                         *.phtml \
+                         *.inc \
+                         *.m \
+                         *.markdown \
+                         *.md \
+                         *.mm \
+                         *.dox \
+                         *.py \
+                         *.pyw \
+                         *.f90 \
+                         *.f95 \
+                         *.f03 \
+                         *.f08 \
+                         *.f18 \
+                         *.f \
+                         *.for \
+                         *.vhd \
+                         *.vhdl \
+                         *.ucf \
+                         *.qsf \
+                         *.ice
+
+# The RECURSIVE tag can be used to specify whether or not subdirectories should
+# be searched for input files as well.
+# The default value is: NO.
+
+RECURSIVE              = NO
+
+# The EXCLUDE tag can be used to specify files and/or directories that should be
+# excluded from the INPUT source files. This way you can easily exclude a
+# subdirectory from a directory tree whose root is specified with the INPUT tag.
+#
+# Note that relative paths are relative to the directory from which doxygen is
+# run.
+
+EXCLUDE                =
+
+# The EXCLUDE_SYMLINKS tag can be used to select whether or not files or
+# directories that are symbolic links (a Unix file system feature) are excluded
+# from the input.
+# The default value is: NO.
+
+EXCLUDE_SYMLINKS       = NO
+
+# If the value of the INPUT tag contains directories, you can use the
+# EXCLUDE_PATTERNS tag to specify one or more wildcard patterns to exclude
+# certain files from those directories.
+#
+# Note that the wildcards are matched against the file with absolute path, so to
+# exclude all test directories for example use the pattern */test/*
+
+EXCLUDE_PATTERNS       =
+
+# The EXCLUDE_SYMBOLS tag can be used to specify one or more symbol names
+# (namespaces, classes, functions, etc.) that should be excluded from the
+# output. The symbol name can be a fully qualified name, a word, or if the
+# wildcard * is used, a substring. Examples: ANamespace, AClass,
+# AClass::ANamespace, ANamespace::*Test
+#
+# Note that the wildcards are matched against the file with absolute path, so to
+# exclude all test directories use the pattern */test/*
+
+EXCLUDE_SYMBOLS        =
+
+# The EXAMPLE_PATH tag can be used to specify one or more files or directories
+# that contain example code fragments that are included (see the \include
+# command).
+
+EXAMPLE_PATH           =
+
+# If the value of the EXAMPLE_PATH tag contains directories, you can use the
+# EXAMPLE_PATTERNS tag to specify one or more wildcard pattern (like *.cpp and
+# *.h) to filter out the source-files in the directories. If left blank all
+# files are included.
+
+EXAMPLE_PATTERNS       = *
+
+# If the EXAMPLE_RECURSIVE tag is set to YES then subdirectories will be
+# searched for input files to be used with the \include or \dontinclude commands
+# irrespective of the value of the RECURSIVE tag.
+# The default value is: NO.
+
+EXAMPLE_RECURSIVE      = NO
+
+# The IMAGE_PATH tag can be used to specify one or more files or directories
+# that contain images that are to be included in the documentation (see the
+# \image command).
+
+IMAGE_PATH             =
+
+# The INPUT_FILTER tag can be used to specify a program that doxygen should
+# invoke to filter for each input file. Doxygen will invoke the filter program
+# by executing (via popen()) the command:
+#
+# <filter> <input-file>
+#
+# where <filter> is the value of the INPUT_FILTER tag, and <input-file> is the
+# name of an input file. Doxygen will then use the output that the filter
+# program writes to standard output. If FILTER_PATTERNS is specified, this tag
+# will be ignored.
+#
+# Note that the filter must not add or remove lines; it is applied before the
+# code is scanned, but not when the output code is generated. If lines are added
+# or removed, the anchors will not be placed correctly.
+#
+# Note that for custom extensions or not directly supported extensions you also
+# need to set EXTENSION_MAPPING for the extension otherwise the files are not
+# properly processed by doxygen.
+
+INPUT_FILTER           =
+
+# The FILTER_PATTERNS tag can be used to specify filters on a per file pattern
+# basis. Doxygen will compare the file name with each pattern and apply the
+# filter if there is a match. The filters are a list of the form: pattern=filter
+# (like *.cpp=my_cpp_filter). See INPUT_FILTER for further information on how
+# filters are used. If the FILTER_PATTERNS tag is empty or if none of the
+# patterns match the file name, INPUT_FILTER is applied.
+#
+# Note that for custom extensions or not directly supported extensions you also
+# need to set EXTENSION_MAPPING for the extension otherwise the files are not
+# properly processed by doxygen.
+
+FILTER_PATTERNS        =
+
+# If the FILTER_SOURCE_FILES tag is set to YES, the input filter (if set using
+# INPUT_FILTER) will also be used to filter the input files that are used for
+# producing the source files to browse (i.e. when SOURCE_BROWSER is set to YES).
+# The default value is: NO.
+
+FILTER_SOURCE_FILES    = NO
+
+# The FILTER_SOURCE_PATTERNS tag can be used to specify source filters per file
+# pattern. A pattern will override the setting for FILTER_PATTERN (if any) and
+# it is also possible to disable source filtering for a specific pattern using
+# *.ext= (so without naming a filter).
+# This tag requires that the tag FILTER_SOURCE_FILES is set to YES.
+
+FILTER_SOURCE_PATTERNS =
+
+# If the USE_MDFILE_AS_MAINPAGE tag refers to the name of a markdown file that
+# is part of the input, its contents will be placed on the main page
+# (index.html). This can be useful if you have a project on for instance GitHub
+# and want to reuse the introduction page also for the doxygen output.
+
+USE_MDFILE_AS_MAINPAGE = @CMAKE_SOURCE_DIR@/README.md
+
+#---------------------------------------------------------------------------
+# Configuration options related to source browsing
+#---------------------------------------------------------------------------
+
+# If the SOURCE_BROWSER tag is set to YES then a list of source files will be
+# generated. Documented entities will be cross-referenced with these sources.
+#
+# Note: To get rid of all source code in the generated output, make sure that
+# also VERBATIM_HEADERS is set to NO.
+# The default value is: NO.
+
+SOURCE_BROWSER         = NO
+
+# Setting the INLINE_SOURCES tag to YES will include the body of functions,
+# classes and enums directly into the documentation.
+# The default value is: NO.
+
+INLINE_SOURCES         = NO
+
+# Setting the STRIP_CODE_COMMENTS tag to YES will instruct doxygen to hide any
+# special comment blocks from generated source code fragments. Normal C, C++ and
+# Fortran comments will always remain visible.
+# The default value is: YES.
+
+STRIP_CODE_COMMENTS    = YES
+
+# If the REFERENCED_BY_RELATION tag is set to YES then for each documented
+# entity all documented functions referencing it will be listed.
+# The default value is: NO.
+
+REFERENCED_BY_RELATION = NO
+
+# If the REFERENCES_RELATION tag is set to YES then for each documented function
+# all documented entities called/used by that function will be listed.
+# The default value is: NO.
+
+REFERENCES_RELATION    = NO
+
+# If the REFERENCES_LINK_SOURCE tag is set to YES and SOURCE_BROWSER tag is set
+# to YES then the hyperlinks from functions in REFERENCES_RELATION and
+# REFERENCED_BY_RELATION lists will link to the source code. Otherwise they will
+# link to the documentation.
+# The default value is: YES.
+
+REFERENCES_LINK_SOURCE = YES
+
+# If SOURCE_TOOLTIPS is enabled (the default) then hovering a hyperlink in the
+# source code will show a tooltip with additional information such as prototype,
+# brief description and links to the definition and documentation. Since this
+# will make the HTML file larger and loading of large files a bit slower, you
+# can opt to disable this feature.
+# The default value is: YES.
+# This tag requires that the tag SOURCE_BROWSER is set to YES.
+
+SOURCE_TOOLTIPS        = YES
+
+# If the USE_HTAGS tag is set to YES then the references to source code will
+# point to the HTML generated by the htags(1) tool instead of doxygen built-in
+# source browser. The htags tool is part of GNU's global source tagging system
+# (see https://www.gnu.org/software/global/global.html). You will need version
+# 4.8.6 or higher.
+#
+# To use it do the following:
+# - Install the latest version of global
+# - Enable SOURCE_BROWSER and USE_HTAGS in the configuration file
+# - Make sure the INPUT points to the root of the source tree
+# - Run doxygen as normal
+#
+# Doxygen will invoke htags (and that will in turn invoke gtags), so these
+# tools must be available from the command line (i.e. in the search path).
+#
+# The result: instead of the source browser generated by doxygen, the links to
+# source code will now point to the output of htags.
+# The default value is: NO.
+# This tag requires that the tag SOURCE_BROWSER is set to YES.
+
+USE_HTAGS              = NO
+
+# If the VERBATIM_HEADERS tag is set the YES then doxygen will generate a
+# verbatim copy of the header file for each class for which an include is
+# specified. Set to NO to disable this.
+# See also: Section \class.
+# The default value is: YES.
+
+VERBATIM_HEADERS       = YES
+
+# If the CLANG_ASSISTED_PARSING tag is set to YES then doxygen will use the
+# clang parser (see:
+# http://clang.llvm.org/) for more accurate parsing at the cost of reduced
+# performance. This can be particularly helpful with template rich C++ code for
+# which doxygen's built-in parser lacks the necessary type information.
+# Note: The availability of this option depends on whether or not doxygen was
+# generated with the -Duse_libclang=ON option for CMake.
+# The default value is: NO.
+
+CLANG_ASSISTED_PARSING = NO
+
+# If clang assisted parsing is enabled and the CLANG_ADD_INC_PATHS tag is set to
+# YES then doxygen will add the directory of each input to the include path.
+# The default value is: YES.
+
+CLANG_ADD_INC_PATHS    = YES
+
+# If clang assisted parsing is enabled you can provide the compiler with command
+# line options that you would normally use when invoking the compiler. Note that
+# the include paths will already be set by doxygen for the files and directories
+# specified with INPUT and INCLUDE_PATH.
+# This tag requires that the tag CLANG_ASSISTED_PARSING is set to YES.
+
+CLANG_OPTIONS          =
+
+# If clang assisted parsing is enabled you can provide the clang parser with the
+# path to the directory containing a file called compile_commands.json. This
+# file is the compilation database (see:
+# http://clang.llvm.org/docs/HowToSetupToolingForLLVM.html) containing the
+# options used when the source files were built. This is equivalent to
+# specifying the -p option to a clang tool, such as clang-check. These options
+# will then be passed to the parser. Any options specified with CLANG_OPTIONS
+# will be added as well.
+# Note: The availability of this option depends on whether or not doxygen was
+# generated with the -Duse_libclang=ON option for CMake.
+
+CLANG_DATABASE_PATH    =
+
+#---------------------------------------------------------------------------
+# Configuration options related to the alphabetical class index
+#---------------------------------------------------------------------------
+
+# If the ALPHABETICAL_INDEX tag is set to YES, an alphabetical index of all
+# compounds will be generated. Enable this if the project contains a lot of
+# classes, structs, unions or interfaces.
+# The default value is: YES.
+
+ALPHABETICAL_INDEX     = YES
+
+# In case all classes in a project start with a common prefix, all classes will
+# be put under the same header in the alphabetical index. The IGNORE_PREFIX tag
+# can be used to specify a prefix (or a list of prefixes) that should be ignored
+# while generating the index headers.
+# This tag requires that the tag ALPHABETICAL_INDEX is set to YES.
+
+IGNORE_PREFIX          =
+
+#---------------------------------------------------------------------------
+# Configuration options related to the HTML output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_HTML tag is set to YES, doxygen will generate HTML output
+# The default value is: YES.
+
+GENERATE_HTML          = YES
+
+# The HTML_OUTPUT tag is used to specify where the HTML docs will be put. If a
+# relative path is entered the value of OUTPUT_DIRECTORY will be put in front of
+# it.
+# The default directory is: html.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_OUTPUT            = html
+
+# The HTML_FILE_EXTENSION tag can be used to specify the file extension for each
+# generated HTML page (for example: .htm, .php, .asp).
+# The default value is: .html.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_FILE_EXTENSION    = .html
+
+# The HTML_HEADER tag can be used to specify a user-defined HTML header file for
+# each generated HTML page. If the tag is left blank doxygen will generate a
+# standard header.
+#
+# To get valid HTML the header file that includes any scripts and style sheets
+# that doxygen needs, which is dependent on the configuration options used (e.g.
+# the setting GENERATE_TREEVIEW). It is highly recommended to start with a
+# default header using
+# doxygen -w html new_header.html new_footer.html new_stylesheet.css
+# YourConfigFile
+# and then modify the file new_header.html. See also section "Doxygen usage"
+# for information on how to generate the default header that doxygen normally
+# uses.
+# Note: The header is subject to change so you typically have to regenerate the
+# default header when upgrading to a newer version of doxygen. For a description
+# of the possible markers and block names see the documentation.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_HEADER            =
+
+# The HTML_FOOTER tag can be used to specify a user-defined HTML footer for each
+# generated HTML page. If the tag is left blank doxygen will generate a standard
+# footer. See HTML_HEADER for more information on how to generate a default
+# footer and what special commands can be used inside the footer. See also
+# section "Doxygen usage" for information on how to generate the default footer
+# that doxygen normally uses.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_FOOTER            =
+
+# The HTML_STYLESHEET tag can be used to specify a user-defined cascading style
+# sheet that is used by each HTML page. It can be used to fine-tune the look of
+# the HTML output. If left blank doxygen will generate a default style sheet.
+# See also section "Doxygen usage" for information on how to generate the style
+# sheet that doxygen normally uses.
+# Note: It is recommended to use HTML_EXTRA_STYLESHEET instead of this tag, as
+# it is more robust and this tag (HTML_STYLESHEET) will in the future become
+# obsolete.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_STYLESHEET        =
+
+# The HTML_EXTRA_STYLESHEET tag can be used to specify additional user-defined
+# cascading style sheets that are included after the standard style sheets
+# created by doxygen. Using this option one can overrule certain style aspects.
+# This is preferred over using HTML_STYLESHEET since it does not replace the
+# standard style sheet and is therefore more robust against future updates.
+# Doxygen will copy the style sheet files to the output directory.
+# Note: The order of the extra style sheet files is of importance (e.g. the last
+# style sheet in the list overrules the setting of the previous ones in the
+# list). For an example see the documentation.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_EXTRA_STYLESHEET  =
+
+# The HTML_EXTRA_FILES tag can be used to specify one or more extra images or
+# other source files which should be copied to the HTML output directory. Note
+# that these files will be copied to the base HTML output directory. Use the
+# $relpath^ marker in the HTML_HEADER and/or HTML_FOOTER files to load these
+# files. In the HTML_STYLESHEET file, use the file name only. Also note that the
+# files will be copied as-is; there are no commands or markers available.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_EXTRA_FILES       =
+
+# The HTML_COLORSTYLE_HUE tag controls the color of the HTML output. Doxygen
+# will adjust the colors in the style sheet and background images according to
+# this color. Hue is specified as an angle on a colorwheel, see
+# https://en.wikipedia.org/wiki/Hue for more information. For instance the value
+# 0 represents red, 60 is yellow, 120 is green, 180 is cyan, 240 is blue, 300
+# purple, and 360 is red again.
+# Minimum value: 0, maximum value: 359, default value: 220.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_COLORSTYLE_HUE    = 220
+
+# The HTML_COLORSTYLE_SAT tag controls the purity (or saturation) of the colors
+# in the HTML output. For a value of 0 the output will use grayscales only. A
+# value of 255 will produce the most vivid colors.
+# Minimum value: 0, maximum value: 255, default value: 100.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_COLORSTYLE_SAT    = 100
+
+# The HTML_COLORSTYLE_GAMMA tag controls the gamma correction applied to the
+# luminance component of the colors in the HTML output. Values below 100
+# gradually make the output lighter, whereas values above 100 make the output
+# darker. The value divided by 100 is the actual gamma applied, so 80 represents
+# a gamma of 0.8, The value 220 represents a gamma of 2.2, and 100 does not
+# change the gamma.
+# Minimum value: 40, maximum value: 240, default value: 80.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_COLORSTYLE_GAMMA  = 80
+
+# If the HTML_TIMESTAMP tag is set to YES then the footer of each generated HTML
+# page will contain the date and time when the page was generated. Setting this
+# to YES can help to show when doxygen was last run and thus if the
+# documentation is up to date.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_TIMESTAMP         = NO
+
+# If the HTML_DYNAMIC_MENUS tag is set to YES then the generated HTML
+# documentation will contain a main index with vertical navigation menus that
+# are dynamically created via JavaScript. If disabled, the navigation index will
+# consists of multiple levels of tabs that are statically embedded in every HTML
+# page. Disable this option to support browsers that do not have JavaScript,
+# like the Qt help browser.
+# The default value is: YES.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_DYNAMIC_MENUS     = YES
+
+# If the HTML_DYNAMIC_SECTIONS tag is set to YES then the generated HTML
+# documentation will contain sections that can be hidden and shown after the
+# page has loaded.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_DYNAMIC_SECTIONS  = NO
+
+# With HTML_INDEX_NUM_ENTRIES one can control the preferred number of entries
+# shown in the various tree structured indices initially; the user can expand
+# and collapse entries dynamically later on. Doxygen will expand the tree to
+# such a level that at most the specified number of entries are visible (unless
+# a fully collapsed tree already exceeds this amount). So setting the number of
+# entries 1 will produce a full collapsed tree by default. 0 is a special value
+# representing an infinite number of entries and will result in a full expanded
+# tree by default.
+# Minimum value: 0, maximum value: 9999, default value: 100.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_INDEX_NUM_ENTRIES = 100
+
+# If the GENERATE_DOCSET tag is set to YES, additional index files will be
+# generated that can be used as input for Apple's Xcode 3 integrated development
+# environment (see:
+# https://developer.apple.com/xcode/), introduced with OSX 10.5 (Leopard). To
+# create a documentation set, doxygen will generate a Makefile in the HTML
+# output directory. Running make will produce the docset in that directory and
+# running make install will install the docset in
+# ~/Library/Developer/Shared/Documentation/DocSets so that Xcode will find it at
+# startup. See https://developer.apple.com/library/archive/featuredarticles/Doxy
+# genXcode/_index.html for more information.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+GENERATE_DOCSET        = NO
+
+# This tag determines the name of the docset feed. A documentation feed provides
+# an umbrella under which multiple documentation sets from a single provider
+# (such as a company or product suite) can be grouped.
+# The default value is: Doxygen generated docs.
+# This tag requires that the tag GENERATE_DOCSET is set to YES.
+
+DOCSET_FEEDNAME        = "Doxygen generated docs"
+
+# This tag specifies a string that should uniquely identify the documentation
+# set bundle. This should be a reverse domain-name style string, e.g.
+# com.mycompany.MyDocSet. Doxygen will append .docset to the name.
+# The default value is: org.doxygen.Project.
+# This tag requires that the tag GENERATE_DOCSET is set to YES.
+
+DOCSET_BUNDLE_ID       = org.doxygen.Project
+
+# The DOCSET_PUBLISHER_ID tag specifies a string that should uniquely identify
+# the documentation publisher. This should be a reverse domain-name style
+# string, e.g. com.mycompany.MyDocSet.documentation.
+# The default value is: org.doxygen.Publisher.
+# This tag requires that the tag GENERATE_DOCSET is set to YES.
+
+DOCSET_PUBLISHER_ID    = org.doxygen.Publisher
+
+# The DOCSET_PUBLISHER_NAME tag identifies the documentation publisher.
+# The default value is: Publisher.
+# This tag requires that the tag GENERATE_DOCSET is set to YES.
+
+DOCSET_PUBLISHER_NAME  = Publisher
+
+# If the GENERATE_HTMLHELP tag is set to YES then doxygen generates three
+# additional HTML index files: index.hhp, index.hhc, and index.hhk. The
+# index.hhp is a project file that can be read by Microsoft's HTML Help Workshop
+# (see:
+# https://www.microsoft.com/en-us/download/details.aspx?id=21138) on Windows.
+#
+# The HTML Help Workshop contains a compiler that can convert all HTML output
+# generated by doxygen into a single compiled HTML file (.chm). Compiled HTML
+# files are now used as the Windows 98 help format, and will replace the old
+# Windows help format (.hlp) on all Windows platforms in the future. Compressed
+# HTML files also contain an index, a table of contents, and you can search for
+# words in the documentation. The HTML workshop also contains a viewer for
+# compressed HTML files.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+GENERATE_HTMLHELP      = NO
+
+# The CHM_FILE tag can be used to specify the file name of the resulting .chm
+# file. You can add a path in front of the file if the result should not be
+# written to the html output directory.
+# This tag requires that the tag GENERATE_HTMLHELP is set to YES.
+
+CHM_FILE               =
+
+# The HHC_LOCATION tag can be used to specify the location (absolute path
+# including file name) of the HTML help compiler (hhc.exe). If non-empty,
+# doxygen will try to run the HTML help compiler on the generated index.hhp.
+# The file has to be specified with full path.
+# This tag requires that the tag GENERATE_HTMLHELP is set to YES.
+
+HHC_LOCATION           =
+
+# The GENERATE_CHI flag controls if a separate .chi index file is generated
+# (YES) or that it should be included in the main .chm file (NO).
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTMLHELP is set to YES.
+
+GENERATE_CHI           = NO
+
+# The CHM_INDEX_ENCODING is used to encode HtmlHelp index (hhk), content (hhc)
+# and project file content.
+# This tag requires that the tag GENERATE_HTMLHELP is set to YES.
+
+CHM_INDEX_ENCODING     =
+
+# The BINARY_TOC flag controls whether a binary table of contents is generated
+# (YES) or a normal table of contents (NO) in the .chm file. Furthermore it
+# enables the Previous and Next buttons.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTMLHELP is set to YES.
+
+BINARY_TOC             = NO
+
+# The TOC_EXPAND flag can be set to YES to add extra items for group members to
+# the table of contents of the HTML help documentation and to the tree view.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTMLHELP is set to YES.
+
+TOC_EXPAND             = NO
+
+# If the GENERATE_QHP tag is set to YES and both QHP_NAMESPACE and
+# QHP_VIRTUAL_FOLDER are set, an additional index file will be generated that
+# can be used as input for Qt's qhelpgenerator to generate a Qt Compressed Help
+# (.qch) of the generated HTML documentation.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+GENERATE_QHP           = NO
+
+# If the QHG_LOCATION tag is specified, the QCH_FILE tag can be used to specify
+# the file name of the resulting .qch file. The path specified is relative to
+# the HTML output folder.
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QCH_FILE               =
+
+# The QHP_NAMESPACE tag specifies the namespace to use when generating Qt Help
+# Project output. For more information please see Qt Help Project / Namespace
+# (see:
+# https://doc.qt.io/archives/qt-4.8/qthelpproject.html#namespace).
+# The default value is: org.doxygen.Project.
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QHP_NAMESPACE          = org.doxygen.Project
+
+# The QHP_VIRTUAL_FOLDER tag specifies the namespace to use when generating Qt
+# Help Project output. For more information please see Qt Help Project / Virtual
+# Folders (see:
+# https://doc.qt.io/archives/qt-4.8/qthelpproject.html#virtual-folders).
+# The default value is: doc.
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QHP_VIRTUAL_FOLDER     = doc
+
+# If the QHP_CUST_FILTER_NAME tag is set, it specifies the name of a custom
+# filter to add. For more information please see Qt Help Project / Custom
+# Filters (see:
+# https://doc.qt.io/archives/qt-4.8/qthelpproject.html#custom-filters).
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QHP_CUST_FILTER_NAME   =
+
+# The QHP_CUST_FILTER_ATTRS tag specifies the list of the attributes of the
+# custom filter to add. For more information please see Qt Help Project / Custom
+# Filters (see:
+# https://doc.qt.io/archives/qt-4.8/qthelpproject.html#custom-filters).
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QHP_CUST_FILTER_ATTRS  =
+
+# The QHP_SECT_FILTER_ATTRS tag specifies the list of the attributes this
+# project's filter section matches. Qt Help Project / Filter Attributes (see:
+# https://doc.qt.io/archives/qt-4.8/qthelpproject.html#filter-attributes).
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QHP_SECT_FILTER_ATTRS  =
+
+# The QHG_LOCATION tag can be used to specify the location (absolute path
+# including file name) of Qt's qhelpgenerator. If non-empty doxygen will try to
+# run qhelpgenerator on the generated .qhp file.
+# This tag requires that the tag GENERATE_QHP is set to YES.
+
+QHG_LOCATION           =
+
+# If the GENERATE_ECLIPSEHELP tag is set to YES, additional index files will be
+# generated, together with the HTML files, they form an Eclipse help plugin. To
+# install this plugin and make it available under the help contents menu in
+# Eclipse, the contents of the directory containing the HTML and XML files needs
+# to be copied into the plugins directory of eclipse. The name of the directory
+# within the plugins directory should be the same as the ECLIPSE_DOC_ID value.
+# After copying Eclipse needs to be restarted before the help appears.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+GENERATE_ECLIPSEHELP   = NO
+
+# A unique identifier for the Eclipse help plugin. When installing the plugin
+# the directory name containing the HTML and XML files should also have this
+# name. Each documentation set should have its own identifier.
+# The default value is: org.doxygen.Project.
+# This tag requires that the tag GENERATE_ECLIPSEHELP is set to YES.
+
+ECLIPSE_DOC_ID         = org.doxygen.Project
+
+# If you want full control over the layout of the generated HTML pages it might
+# be necessary to disable the index and replace it with your own. The
+# DISABLE_INDEX tag can be used to turn on/off the condensed index (tabs) at top
+# of each HTML page. A value of NO enables the index and the value YES disables
+# it. Since the tabs in the index contain the same information as the navigation
+# tree, you can set this option to YES if you also set GENERATE_TREEVIEW to YES.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+DISABLE_INDEX          = NO
+
+# The GENERATE_TREEVIEW tag is used to specify whether a tree-like index
+# structure should be generated to display hierarchical information. If the tag
+# value is set to YES, a side panel will be generated containing a tree-like
+# index structure (just like the one that is generated for HTML Help). For this
+# to work a browser that supports JavaScript, DHTML, CSS and frames is required
+# (i.e. any modern browser). Windows users are probably better off using the
+# HTML help feature. Via custom style sheets (see HTML_EXTRA_STYLESHEET) one can
+# further fine-tune the look of the index. As an example, the default style
+# sheet generated by doxygen has an example that shows how to put an image at
+# the root of the tree instead of the PROJECT_NAME. Since the tree basically has
+# the same information as the tab index, you could consider setting
+# DISABLE_INDEX to YES when enabling this option.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+GENERATE_TREEVIEW      = NO
+
+# The ENUM_VALUES_PER_LINE tag can be used to set the number of enum values that
+# doxygen will group on one line in the generated HTML documentation.
+#
+# Note that a value of 0 will completely suppress the enum values from appearing
+# in the overview section.
+# Minimum value: 0, maximum value: 20, default value: 4.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+ENUM_VALUES_PER_LINE   = 4
+
+# If the treeview is enabled (see GENERATE_TREEVIEW) then this tag can be used
+# to set the initial width (in pixels) of the frame in which the tree is shown.
+# Minimum value: 0, maximum value: 1500, default value: 250.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+TREEVIEW_WIDTH         = 250
+
+# If the EXT_LINKS_IN_WINDOW option is set to YES, doxygen will open links to
+# external symbols imported via tag files in a separate window.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+EXT_LINKS_IN_WINDOW    = NO
+
+# If the HTML_FORMULA_FORMAT option is set to svg, doxygen will use the pdf2svg
+# tool (see https://github.com/dawbarton/pdf2svg) or inkscape (see
+# https://inkscape.org) to generate formulas as SVG images instead of PNGs for
+# the HTML output. These images will generally look nicer at scaled resolutions.
+# Possible values are: png (the default) and svg (looks nicer but requires the
+# pdf2svg or inkscape tool).
+# The default value is: png.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+HTML_FORMULA_FORMAT    = png
+
+# Use this tag to change the font size of LaTeX formulas included as images in
+# the HTML documentation. When you change the font size after a successful
+# doxygen run you need to manually remove any form_*.png images from the HTML
+# output directory to force them to be regenerated.
+# Minimum value: 8, maximum value: 50, default value: 10.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+FORMULA_FONTSIZE       = 10
+
+# Use the FORMULA_TRANSPARENT tag to determine whether or not the images
+# generated for formulas are transparent PNGs. Transparent PNGs are not
+# supported properly for IE 6.0, but are supported on all modern browsers.
+#
+# Note that when changing this option you need to delete any form_*.png files in
+# the HTML output directory before the changes have effect.
+# The default value is: YES.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+FORMULA_TRANSPARENT    = YES
+
+# The FORMULA_MACROFILE can contain LaTeX \newcommand and \renewcommand commands
+# to create new LaTeX commands to be used in formulas as building blocks. See
+# the section "Including formulas" for details.
+
+FORMULA_MACROFILE      =
+
+# Enable the USE_MATHJAX option to render LaTeX formulas using MathJax (see
+# https://www.mathjax.org) which uses client side JavaScript for the rendering
+# instead of using pre-rendered bitmaps. Use this if you do not have LaTeX
+# installed or if you want to formulas look prettier in the HTML output. When
+# enabled you may also need to install MathJax separately and configure the path
+# to it using the MATHJAX_RELPATH option.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+USE_MATHJAX            = NO
+
+# When MathJax is enabled you can set the default output format to be used for
+# the MathJax output. See the MathJax site (see:
+# http://docs.mathjax.org/en/v2.7-latest/output.html) for more details.
+# Possible values are: HTML-CSS (which is slower, but has the best
+# compatibility), NativeMML (i.e. MathML) and SVG.
+# The default value is: HTML-CSS.
+# This tag requires that the tag USE_MATHJAX is set to YES.
+
+MATHJAX_FORMAT         = HTML-CSS
+
+# When MathJax is enabled you need to specify the location relative to the HTML
+# output directory using the MATHJAX_RELPATH option. The destination directory
+# should contain the MathJax.js script. For instance, if the mathjax directory
+# is located at the same level as the HTML output directory, then
+# MATHJAX_RELPATH should be ../mathjax. The default value points to the MathJax
+# Content Delivery Network so you can quickly see the result without installing
+# MathJax. However, it is strongly recommended to install a local copy of
+# MathJax from https://www.mathjax.org before deployment.
+# The default value is: https://cdn.jsdelivr.net/npm/mathjax@2.
+# This tag requires that the tag USE_MATHJAX is set to YES.
+
+MATHJAX_RELPATH        = https://cdn.jsdelivr.net/npm/mathjax@2
+
+# The MATHJAX_EXTENSIONS tag can be used to specify one or more MathJax
+# extension names that should be enabled during MathJax rendering. For example
+# MATHJAX_EXTENSIONS = TeX/AMSmath TeX/AMSsymbols
+# This tag requires that the tag USE_MATHJAX is set to YES.
+
+MATHJAX_EXTENSIONS     =
+
+# The MATHJAX_CODEFILE tag can be used to specify a file with javascript pieces
+# of code that will be used on startup of the MathJax code. See the MathJax site
+# (see:
+# http://docs.mathjax.org/en/v2.7-latest/output.html) for more details. For an
+# example see the documentation.
+# This tag requires that the tag USE_MATHJAX is set to YES.
+
+MATHJAX_CODEFILE       =
+
+# When the SEARCHENGINE tag is enabled doxygen will generate a search box for
+# the HTML output. The underlying search engine uses javascript and DHTML and
+# should work on any modern browser. Note that when using HTML help
+# (GENERATE_HTMLHELP), Qt help (GENERATE_QHP), or docsets (GENERATE_DOCSET)
+# there is already a search function so this one should typically be disabled.
+# For large projects the javascript based search engine can be slow, then
+# enabling SERVER_BASED_SEARCH may provide a better solution. It is possible to
+# search using the keyboard; to jump to the search box use <access key> + S
+# (what the <access key> is depends on the OS and browser, but it is typically
+# <CTRL>, <ALT>/<option>, or both). Inside the search box use the <cursor down
+# key> to jump into the search results window, the results can be navigated
+# using the <cursor keys>. Press <Enter> to select an item or <escape> to cancel
+# the search. The filter options can be selected when the cursor is inside the
+# search box by pressing <Shift>+<cursor down>. Also here use the <cursor keys>
+# to select a filter and <Enter> or <escape> to activate or cancel the filter
+# option.
+# The default value is: YES.
+# This tag requires that the tag GENERATE_HTML is set to YES.
+
+SEARCHENGINE           = YES
+
+# When the SERVER_BASED_SEARCH tag is enabled the search engine will be
+# implemented using a web server instead of a web client using JavaScript. There
+# are two flavors of web server based searching depending on the EXTERNAL_SEARCH
+# setting. When disabled, doxygen will generate a PHP script for searching and
+# an index file used by the script. When EXTERNAL_SEARCH is enabled the indexing
+# and searching needs to be provided by external tools. See the section
+# "External Indexing and Searching" for details.
+# The default value is: NO.
+# This tag requires that the tag SEARCHENGINE is set to YES.
+
+SERVER_BASED_SEARCH    = NO
+
+# When EXTERNAL_SEARCH tag is enabled doxygen will no longer generate the PHP
+# script for searching. Instead the search results are written to an XML file
+# which needs to be processed by an external indexer. Doxygen will invoke an
+# external search engine pointed to by the SEARCHENGINE_URL option to obtain the
+# search results.
+#
+# Doxygen ships with an example indexer (doxyindexer) and search engine
+# (doxysearch.cgi) which are based on the open source search engine library
+# Xapian (see:
+# https://xapian.org/).
+#
+# See the section "External Indexing and Searching" for details.
+# The default value is: NO.
+# This tag requires that the tag SEARCHENGINE is set to YES.
+
+EXTERNAL_SEARCH        = NO
+
+# The SEARCHENGINE_URL should point to a search engine hosted by a web server
+# which will return the search results when EXTERNAL_SEARCH is enabled.
+#
+# Doxygen ships with an example indexer (doxyindexer) and search engine
+# (doxysearch.cgi) which are based on the open source search engine library
+# Xapian (see:
+# https://xapian.org/). See the section "External Indexing and Searching" for
+# details.
+# This tag requires that the tag SEARCHENGINE is set to YES.
+
+SEARCHENGINE_URL       =
+
+# When SERVER_BASED_SEARCH and EXTERNAL_SEARCH are both enabled the unindexed
+# search data is written to a file for indexing by an external tool. With the
+# SEARCHDATA_FILE tag the name of this file can be specified.
+# The default file is: searchdata.xml.
+# This tag requires that the tag SEARCHENGINE is set to YES.
+
+SEARCHDATA_FILE        = searchdata.xml
+
+# When SERVER_BASED_SEARCH and EXTERNAL_SEARCH are both enabled the
+# EXTERNAL_SEARCH_ID tag can be used as an identifier for the project. This is
+# useful in combination with EXTRA_SEARCH_MAPPINGS to search through multiple
+# projects and redirect the results back to the right project.
+# This tag requires that the tag SEARCHENGINE is set to YES.
+
+EXTERNAL_SEARCH_ID     =
+
+# The EXTRA_SEARCH_MAPPINGS tag can be used to enable searching through doxygen
+# projects other than the one defined by this configuration file, but that are
+# all added to the same external search index. Each project needs to have a
+# unique id set via EXTERNAL_SEARCH_ID. The search mapping then maps the id of
+# to a relative location where the documentation can be found. The format is:
+# EXTRA_SEARCH_MAPPINGS = tagname1=loc1 tagname2=loc2 ...
+# This tag requires that the tag SEARCHENGINE is set to YES.
+
+EXTRA_SEARCH_MAPPINGS  =
+
+#---------------------------------------------------------------------------
+# Configuration options related to the LaTeX output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_LATEX tag is set to YES, doxygen will generate LaTeX output.
+# The default value is: YES.
+
+GENERATE_LATEX         = YES
+
+# The LATEX_OUTPUT tag is used to specify where the LaTeX docs will be put. If a
+# relative path is entered the value of OUTPUT_DIRECTORY will be put in front of
+# it.
+# The default directory is: latex.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_OUTPUT           = latex
+
+# The LATEX_CMD_NAME tag can be used to specify the LaTeX command name to be
+# invoked.
+#
+# Note that when not enabling USE_PDFLATEX the default is latex when enabling
+# USE_PDFLATEX the default is pdflatex and when in the later case latex is
+# chosen this is overwritten by pdflatex. For specific output languages the
+# default can have been set differently, this depends on the implementation of
+# the output language.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_CMD_NAME         =
+
+# The MAKEINDEX_CMD_NAME tag can be used to specify the command name to generate
+# index for LaTeX.
+# Note: This tag is used in the Makefile / make.bat.
+# See also: LATEX_MAKEINDEX_CMD for the part in the generated output file
+# (.tex).
+# The default file is: makeindex.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+MAKEINDEX_CMD_NAME     = makeindex
+
+# The LATEX_MAKEINDEX_CMD tag can be used to specify the command name to
+# generate index for LaTeX. In case there is no backslash (\) as first character
+# it will be automatically added in the LaTeX code.
+# Note: This tag is used in the generated output file (.tex).
+# See also: MAKEINDEX_CMD_NAME for the part in the Makefile / make.bat.
+# The default value is: makeindex.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_MAKEINDEX_CMD    = makeindex
+
+# If the COMPACT_LATEX tag is set to YES, doxygen generates more compact LaTeX
+# documents. This may be useful for small projects and may help to save some
+# trees in general.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+COMPACT_LATEX          = NO
+
+# The PAPER_TYPE tag can be used to set the paper type that is used by the
+# printer.
+# Possible values are: a4 (210 x 297 mm), letter (8.5 x 11 inches), legal (8.5 x
+# 14 inches) and executive (7.25 x 10.5 inches).
+# The default value is: a4.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+PAPER_TYPE             = a4
+
+# The EXTRA_PACKAGES tag can be used to specify one or more LaTeX package names
+# that should be included in the LaTeX output. The package can be specified just
+# by its name or with the correct syntax as to be used with the LaTeX
+# \usepackage command. To get the times font for instance you can specify :
+# EXTRA_PACKAGES=times or EXTRA_PACKAGES={times}
+# To use the option intlimits with the amsmath package you can specify:
+# EXTRA_PACKAGES=[intlimits]{amsmath}
+# If left blank no extra packages will be included.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+EXTRA_PACKAGES         =
+
+# The LATEX_HEADER tag can be used to specify a personal LaTeX header for the
+# generated LaTeX document. The header should contain everything until the first
+# chapter. If it is left blank doxygen will generate a standard header. See
+# section "Doxygen usage" for information on how to let doxygen write the
+# default header to a separate file.
+#
+# Note: Only use a user-defined header if you know what you are doing! The
+# following commands have a special meaning inside the header: $title,
+# $datetime, $date, $doxygenversion, $projectname, $projectnumber,
+# $projectbrief, $projectlogo. Doxygen will replace $title with the empty
+# string, for the replacement values of the other commands the user is referred
+# to HTML_HEADER.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_HEADER           =
+
+# The LATEX_FOOTER tag can be used to specify a personal LaTeX footer for the
+# generated LaTeX document. The footer should contain everything after the last
+# chapter. If it is left blank doxygen will generate a standard footer. See
+# LATEX_HEADER for more information on how to generate a default footer and what
+# special commands can be used inside the footer.
+#
+# Note: Only use a user-defined footer if you know what you are doing!
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_FOOTER           =
+
+# The LATEX_EXTRA_STYLESHEET tag can be used to specify additional user-defined
+# LaTeX style sheets that are included after the standard style sheets created
+# by doxygen. Using this option one can overrule certain style aspects. Doxygen
+# will copy the style sheet files to the output directory.
+# Note: The order of the extra style sheet files is of importance (e.g. the last
+# style sheet in the list overrules the setting of the previous ones in the
+# list).
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_EXTRA_STYLESHEET =
+
+# The LATEX_EXTRA_FILES tag can be used to specify one or more extra images or
+# other source files which should be copied to the LATEX_OUTPUT output
+# directory. Note that the files will be copied as-is; there are no commands or
+# markers available.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_EXTRA_FILES      =
+
+# If the PDF_HYPERLINKS tag is set to YES, the LaTeX that is generated is
+# prepared for conversion to PDF (using ps2pdf or pdflatex). The PDF file will
+# contain links (just like the HTML output) instead of page references. This
+# makes the output suitable for online browsing using a PDF viewer.
+# The default value is: YES.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+PDF_HYPERLINKS         = YES
+
+# If the USE_PDFLATEX tag is set to YES, doxygen will use the engine as
+# specified with LATEX_CMD_NAME to generate the PDF file directly from the LaTeX
+# files. Set this option to YES, to get a higher quality PDF documentation.
+#
+# See also section LATEX_CMD_NAME for selecting the engine.
+# The default value is: YES.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+USE_PDFLATEX           = YES
+
+# If the LATEX_BATCHMODE tag is set to YES, doxygen will add the \batchmode
+# command to the generated LaTeX files. This will instruct LaTeX to keep running
+# if errors occur, instead of asking the user for help. This option is also used
+# when generating formulas in HTML.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_BATCHMODE        = NO
+
+# If the LATEX_HIDE_INDICES tag is set to YES then doxygen will not include the
+# index chapters (such as File Index, Compound Index, etc.) in the output.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_HIDE_INDICES     = NO
+
+# The LATEX_BIB_STYLE tag can be used to specify the style to use for the
+# bibliography, e.g. plainnat, or ieeetr. See
+# https://en.wikipedia.org/wiki/BibTeX and \cite for more info.
+# The default value is: plain.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_BIB_STYLE        = plain
+
+# If the LATEX_TIMESTAMP tag is set to YES then the footer of each generated
+# page will contain the date and time when the page was generated. Setting this
+# to NO can help when comparing the output of multiple runs.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_TIMESTAMP        = NO
+
+# The LATEX_EMOJI_DIRECTORY tag is used to specify the (relative or absolute)
+# path from which the emoji images will be read. If a relative path is entered,
+# it will be relative to the LATEX_OUTPUT directory. If left blank the
+# LATEX_OUTPUT directory will be used.
+# This tag requires that the tag GENERATE_LATEX is set to YES.
+
+LATEX_EMOJI_DIRECTORY  =
+
+#---------------------------------------------------------------------------
+# Configuration options related to the RTF output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_RTF tag is set to YES, doxygen will generate RTF output. The
+# RTF output is optimized for Word 97 and may not look too pretty with other RTF
+# readers/editors.
+# The default value is: NO.
+
+GENERATE_RTF           = NO
+
+# The RTF_OUTPUT tag is used to specify where the RTF docs will be put. If a
+# relative path is entered the value of OUTPUT_DIRECTORY will be put in front of
+# it.
+# The default directory is: rtf.
+# This tag requires that the tag GENERATE_RTF is set to YES.
+
+RTF_OUTPUT             = rtf
+
+# If the COMPACT_RTF tag is set to YES, doxygen generates more compact RTF
+# documents. This may be useful for small projects and may help to save some
+# trees in general.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_RTF is set to YES.
+
+COMPACT_RTF            = NO
+
+# If the RTF_HYPERLINKS tag is set to YES, the RTF that is generated will
+# contain hyperlink fields. The RTF file will contain links (just like the HTML
+# output) instead of page references. This makes the output suitable for online
+# browsing using Word or some other Word compatible readers that support those
+# fields.
+#
+# Note: WordPad (write) and others do not support links.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_RTF is set to YES.
+
+RTF_HYPERLINKS         = NO
+
+# Load stylesheet definitions from file. Syntax is similar to doxygen's
+# configuration file, i.e. a series of assignments. You only have to provide
+# replacements, missing definitions are set to their default value.
+#
+# See also section "Doxygen usage" for information on how to generate the
+# default style sheet that doxygen normally uses.
+# This tag requires that the tag GENERATE_RTF is set to YES.
+
+RTF_STYLESHEET_FILE    =
+
+# Set optional variables used in the generation of an RTF document. Syntax is
+# similar to doxygen's configuration file. A template extensions file can be
+# generated using doxygen -e rtf extensionFile.
+# This tag requires that the tag GENERATE_RTF is set to YES.
+
+RTF_EXTENSIONS_FILE    =
+
+#---------------------------------------------------------------------------
+# Configuration options related to the man page output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_MAN tag is set to YES, doxygen will generate man pages for
+# classes and files.
+# The default value is: NO.
+
+GENERATE_MAN           = NO
+
+# The MAN_OUTPUT tag is used to specify where the man pages will be put. If a
+# relative path is entered the value of OUTPUT_DIRECTORY will be put in front of
+# it. A directory man3 will be created inside the directory specified by
+# MAN_OUTPUT.
+# The default directory is: man.
+# This tag requires that the tag GENERATE_MAN is set to YES.
+
+MAN_OUTPUT             = man
+
+# The MAN_EXTENSION tag determines the extension that is added to the generated
+# man pages. In case the manual section does not start with a number, the number
+# 3 is prepended. The dot (.) at the beginning of the MAN_EXTENSION tag is
+# optional.
+# The default value is: .3.
+# This tag requires that the tag GENERATE_MAN is set to YES.
+
+MAN_EXTENSION          = .3
+
+# The MAN_SUBDIR tag determines the name of the directory created within
+# MAN_OUTPUT in which the man pages are placed. If defaults to man followed by
+# MAN_EXTENSION with the initial . removed.
+# This tag requires that the tag GENERATE_MAN is set to YES.
+
+MAN_SUBDIR             =
+
+# If the MAN_LINKS tag is set to YES and doxygen generates man output, then it
+# will generate one additional man file for each entity documented in the real
+# man page(s). These additional files only source the real man page, but without
+# them the man command would be unable to find the correct page.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_MAN is set to YES.
+
+MAN_LINKS              = NO
+
+#---------------------------------------------------------------------------
+# Configuration options related to the XML output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_XML tag is set to YES, doxygen will generate an XML file that
+# captures the structure of the code including all documentation.
+# The default value is: NO.
+
+GENERATE_XML           = NO
+
+# The XML_OUTPUT tag is used to specify where the XML pages will be put. If a
+# relative path is entered the value of OUTPUT_DIRECTORY will be put in front of
+# it.
+# The default directory is: xml.
+# This tag requires that the tag GENERATE_XML is set to YES.
+
+XML_OUTPUT             = xml
+
+# If the XML_PROGRAMLISTING tag is set to YES, doxygen will dump the program
+# listings (including syntax highlighting and cross-referencing information) to
+# the XML output. Note that enabling this will significantly increase the size
+# of the XML output.
+# The default value is: YES.
+# This tag requires that the tag GENERATE_XML is set to YES.
+
+XML_PROGRAMLISTING     = YES
+
+# If the XML_NS_MEMB_FILE_SCOPE tag is set to YES, doxygen will include
+# namespace members in file scope as well, matching the HTML output.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_XML is set to YES.
+
+XML_NS_MEMB_FILE_SCOPE = NO
+
+#---------------------------------------------------------------------------
+# Configuration options related to the DOCBOOK output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_DOCBOOK tag is set to YES, doxygen will generate Docbook files
+# that can be used to generate PDF.
+# The default value is: NO.
+
+GENERATE_DOCBOOK       = NO
+
+# The DOCBOOK_OUTPUT tag is used to specify where the Docbook pages will be put.
+# If a relative path is entered the value of OUTPUT_DIRECTORY will be put in
+# front of it.
+# The default directory is: docbook.
+# This tag requires that the tag GENERATE_DOCBOOK is set to YES.
+
+DOCBOOK_OUTPUT         = docbook
+
+#---------------------------------------------------------------------------
+# Configuration options for the AutoGen Definitions output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_AUTOGEN_DEF tag is set to YES, doxygen will generate an
+# AutoGen Definitions (see http://autogen.sourceforge.net/) file that captures
+# the structure of the code including all documentation. Note that this feature
+# is still experimental and incomplete at the moment.
+# The default value is: NO.
+
+GENERATE_AUTOGEN_DEF   = NO
+
+#---------------------------------------------------------------------------
+# Configuration options related to the Perl module output
+#---------------------------------------------------------------------------
+
+# If the GENERATE_PERLMOD tag is set to YES, doxygen will generate a Perl module
+# file that captures the structure of the code including all documentation.
+#
+# Note that this feature is still experimental and incomplete at the moment.
+# The default value is: NO.
+
+GENERATE_PERLMOD       = NO
+
+# If the PERLMOD_LATEX tag is set to YES, doxygen will generate the necessary
+# Makefile rules, Perl scripts and LaTeX code to be able to generate PDF and DVI
+# output from the Perl module output.
+# The default value is: NO.
+# This tag requires that the tag GENERATE_PERLMOD is set to YES.
+
+PERLMOD_LATEX          = NO
+
+# If the PERLMOD_PRETTY tag is set to YES, the Perl module output will be nicely
+# formatted so it can be parsed by a human reader. This is useful if you want to
+# understand what is going on. On the other hand, if this tag is set to NO, the
+# size of the Perl module output will be much smaller and Perl will parse it
+# just the same.
+# The default value is: YES.
+# This tag requires that the tag GENERATE_PERLMOD is set to YES.
+
+PERLMOD_PRETTY         = YES
+
+# The names of the make variables in the generated doxyrules.make file are
+# prefixed with the string contained in PERLMOD_MAKEVAR_PREFIX. This is useful
+# so different doxyrules.make files included by the same Makefile don't
+# overwrite each other's variables.
+# This tag requires that the tag GENERATE_PERLMOD is set to YES.
+
+PERLMOD_MAKEVAR_PREFIX =
+
+#---------------------------------------------------------------------------
+# Configuration options related to the preprocessor
+#---------------------------------------------------------------------------
+
+# If the ENABLE_PREPROCESSING tag is set to YES, doxygen will evaluate all
+# C-preprocessor directives found in the sources and include files.
+# The default value is: YES.
+
+ENABLE_PREPROCESSING   = YES
+
+# If the MACRO_EXPANSION tag is set to YES, doxygen will expand all macro names
+# in the source code. If set to NO, only conditional compilation will be
+# performed. Macro expansion can be done in a controlled way by setting
+# EXPAND_ONLY_PREDEF to YES.
+# The default value is: NO.
+# This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
+
+MACRO_EXPANSION        = NO
+
+# If the EXPAND_ONLY_PREDEF and MACRO_EXPANSION tags are both set to YES then
+# the macro expansion is limited to the macros specified with the PREDEFINED and
+# EXPAND_AS_DEFINED tags.
+# The default value is: NO.
+# This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
+
+EXPAND_ONLY_PREDEF     = NO
+
+# If the SEARCH_INCLUDES tag is set to YES, the include files in the
+# INCLUDE_PATH will be searched if a #include is found.
+# The default value is: YES.
+# This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
+
+SEARCH_INCLUDES        = YES
+
+# The INCLUDE_PATH tag can be used to specify one or more directories that
+# contain include files that are not input files but should be processed by the
+# preprocessor.
+# This tag requires that the tag SEARCH_INCLUDES is set to YES.
+
+INCLUDE_PATH           =
+
+# You can use the INCLUDE_FILE_PATTERNS tag to specify one or more wildcard
+# patterns (like *.h and *.hpp) to filter out the header-files in the
+# directories. If left blank, the patterns specified with FILE_PATTERNS will be
+# used.
+# This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
+
+INCLUDE_FILE_PATTERNS  =
+
+# The PREDEFINED tag can be used to specify one or more macro names that are
+# defined before the preprocessor is started (similar to the -D option of e.g.
+# gcc). The argument of the tag is a list of macros of the form: name or
+# name=definition (no spaces). If the definition and the "=" are omitted, "=1"
+# is assumed. To prevent a macro definition from being undefined via #undef or
+# recursively expanded use the := operator instead of the = operator.
+# This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
+
+PREDEFINED             =
+
+# If the MACRO_EXPANSION and EXPAND_ONLY_PREDEF tags are set to YES then this
+# tag can be used to specify a list of macro names that should be expanded. The
+# macro definition that is found in the sources will be used. Use the PREDEFINED
+# tag if you want to use a different macro definition that overrules the
+# definition found in the source code.
+# This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
+
+EXPAND_AS_DEFINED      =
+
+# If the SKIP_FUNCTION_MACROS tag is set to YES then doxygen's preprocessor will
+# remove all references to function-like macros that are alone on a line, have
+# an all uppercase name, and do not end with a semicolon. Such function macros
+# are typically used for boiler-plate code, and will confuse the parser if not
+# removed.
+# The default value is: YES.
+# This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
+
+SKIP_FUNCTION_MACROS   = YES
+
+#---------------------------------------------------------------------------
+# Configuration options related to external references
+#---------------------------------------------------------------------------
+
+# The TAGFILES tag can be used to specify one or more tag files. For each tag
+# file the location of the external documentation should be added. The format of
+# a tag file without this location is as follows:
+# TAGFILES = file1 file2 ...
+# Adding location for the tag files is done as follows:
+# TAGFILES = file1=loc1 "file2 = loc2" ...
+# where loc1 and loc2 can be relative or absolute paths or URLs. See the
+# section "Linking to external documentation" for more information about the use
+# of tag files.
+# Note: Each tag file must have a unique name (where the name does NOT include
+# the path). If a tag file is not located in the directory in which doxygen is
+# run, you must also specify the path to the tagfile here.
+
+TAGFILES               =
+
+# When a file name is specified after GENERATE_TAGFILE, doxygen will create a
+# tag file that is based on the input files it reads. See section "Linking to
+# external documentation" for more information about the usage of tag files.
+
+GENERATE_TAGFILE       =
+
+# If the ALLEXTERNALS tag is set to YES, all external class will be listed in
+# the class index. If set to NO, only the inherited external classes will be
+# listed.
+# The default value is: NO.
+
+ALLEXTERNALS           = NO
+
+# If the EXTERNAL_GROUPS tag is set to YES, all external groups will be listed
+# in the modules index. If set to NO, only the current project's groups will be
+# listed.
+# The default value is: YES.
+
+EXTERNAL_GROUPS        = YES
+
+# If the EXTERNAL_PAGES tag is set to YES, all external pages will be listed in
+# the related pages index. If set to NO, only the current project's pages will
+# be listed.
+# The default value is: YES.
+
+EXTERNAL_PAGES         = YES
+
+#---------------------------------------------------------------------------
+# Configuration options related to the dot tool
+#---------------------------------------------------------------------------
+
+# You can include diagrams made with dia in doxygen documentation. Doxygen will
+# then run dia to produce the diagram and insert it in the documentation. The
+# DIA_PATH tag allows you to specify the directory where the dia binary resides.
+# If left empty dia is assumed to be found in the default search path.
+
+DIA_PATH               =
+
+# If set to YES the inheritance and collaboration graphs will hide inheritance
+# and usage relations if the target is undocumented or is not a class.
+# The default value is: YES.
+
+HIDE_UNDOC_RELATIONS   = YES
+
+# If you set the HAVE_DOT tag to YES then doxygen will assume the dot tool is
+# available from the path. This tool is part of Graphviz (see:
+# http://www.graphviz.org/), a graph visualization toolkit from AT&T and Lucent
+# Bell Labs. The other options in this section have no effect if this option is
+# set to NO
+# The default value is: YES.
+
+HAVE_DOT               = YES
+
+# The DOT_NUM_THREADS specifies the number of dot invocations doxygen is allowed
+# to run in parallel. When set to 0 doxygen will base this on the number of
+# processors available in the system. You can set it explicitly to a value
+# larger than 0 to get control over the balance between CPU load and processing
+# speed.
+# Minimum value: 0, maximum value: 32, default value: 0.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_NUM_THREADS        = 0
+
+# When you want a differently looking font in the dot files that doxygen
+# generates you can specify the font name using DOT_FONTNAME. You need to make
+# sure dot is able to find the font, which can be done by putting it in a
+# standard location or by setting the DOTFONTPATH environment variable or by
+# setting DOT_FONTPATH to the directory containing the font.
+# The default value is: Helvetica.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_FONTNAME           = Helvetica
+
+# The DOT_FONTSIZE tag can be used to set the size (in points) of the font of
+# dot graphs.
+# Minimum value: 4, maximum value: 24, default value: 10.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_FONTSIZE           = 10
+
+# By default doxygen will tell dot to use the default font as specified with
+# DOT_FONTNAME. If you specify a different font using DOT_FONTNAME you can set
+# the path where dot can find it using this tag.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_FONTPATH           =
+
+# If the CLASS_GRAPH tag is set to YES then doxygen will generate a graph for
+# each documented class showing the direct and indirect inheritance relations.
+# Setting this tag to YES will force the CLASS_DIAGRAMS tag to NO.
+# The default value is: YES.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+CLASS_GRAPH            = YES
+
+# If the COLLABORATION_GRAPH tag is set to YES then doxygen will generate a
+# graph for each documented class showing the direct and indirect implementation
+# dependencies (inheritance, containment, and class references variables) of the
+# class with other documented classes.
+# The default value is: YES.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+COLLABORATION_GRAPH    = YES
+
+# If the GROUP_GRAPHS tag is set to YES then doxygen will generate a graph for
+# groups, showing the direct groups dependencies.
+# The default value is: YES.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+GROUP_GRAPHS           = YES
+
+# If the UML_LOOK tag is set to YES, doxygen will generate inheritance and
+# collaboration diagrams in a style similar to the OMG's Unified Modeling
+# Language.
+# The default value is: NO.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+UML_LOOK               = NO
+
+# If the UML_LOOK tag is enabled, the fields and methods are shown inside the
+# class node. If there are many fields or methods and many nodes the graph may
+# become too big to be useful. The UML_LIMIT_NUM_FIELDS threshold limits the
+# number of items for each type to make the size more manageable. Set this to 0
+# for no limit. Note that the threshold may be exceeded by 50% before the limit
+# is enforced. So when you set the threshold to 10, up to 15 fields may appear,
+# but if the number exceeds 15, the total amount of fields shown is limited to
+# 10.
+# Minimum value: 0, maximum value: 100, default value: 10.
+# This tag requires that the tag UML_LOOK is set to YES.
+
+UML_LIMIT_NUM_FIELDS   = 10
+
+# If the DOT_UML_DETAILS tag is set to NO, doxygen will show attributes and
+# methods without types and arguments in the UML graphs. If the DOT_UML_DETAILS
+# tag is set to YES, doxygen will add type and arguments for attributes and
+# methods in the UML graphs. If the DOT_UML_DETAILS tag is set to NONE, doxygen
+# will not generate fields with class member information in the UML graphs. The
+# class diagrams will look similar to the default class diagrams but using UML
+# notation for the relationships.
+# Possible values are: NO, YES and NONE.
+# The default value is: NO.
+# This tag requires that the tag UML_LOOK is set to YES.
+
+DOT_UML_DETAILS        = NO
+
+# The DOT_WRAP_THRESHOLD tag can be used to set the maximum number of characters
+# to display on a single line. If the actual line length exceeds this threshold
+# significantly it will wrapped across multiple lines. Some heuristics are apply
+# to avoid ugly line breaks.
+# Minimum value: 0, maximum value: 1000, default value: 17.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_WRAP_THRESHOLD     = 17
+
+# If the TEMPLATE_RELATIONS tag is set to YES then the inheritance and
+# collaboration graphs will show the relations between templates and their
+# instances.
+# The default value is: NO.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+TEMPLATE_RELATIONS     = NO
+
+# If the INCLUDE_GRAPH, ENABLE_PREPROCESSING and SEARCH_INCLUDES tags are set to
+# YES then doxygen will generate a graph for each documented file showing the
+# direct and indirect include dependencies of the file with other documented
+# files.
+# The default value is: YES.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+INCLUDE_GRAPH          = YES
+
+# If the INCLUDED_BY_GRAPH, ENABLE_PREPROCESSING and SEARCH_INCLUDES tags are
+# set to YES then doxygen will generate a graph for each documented file showing
+# the direct and indirect include dependencies of the file with other documented
+# files.
+# The default value is: YES.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+INCLUDED_BY_GRAPH      = YES
+
+# If the CALL_GRAPH tag is set to YES then doxygen will generate a call
+# dependency graph for every global function or class method.
+#
+# Note that enabling this option will significantly increase the time of a run.
+# So in most cases it will be better to enable call graphs for selected
+# functions only using the \callgraph command. Disabling a call graph can be
+# accomplished by means of the command \hidecallgraph.
+# The default value is: NO.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+CALL_GRAPH             = NO
+
+# If the CALLER_GRAPH tag is set to YES then doxygen will generate a caller
+# dependency graph for every global function or class method.
+#
+# Note that enabling this option will significantly increase the time of a run.
+# So in most cases it will be better to enable caller graphs for selected
+# functions only using the \callergraph command. Disabling a caller graph can be
+# accomplished by means of the command \hidecallergraph.
+# The default value is: NO.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+CALLER_GRAPH           = NO
+
+# If the GRAPHICAL_HIERARCHY tag is set to YES then doxygen will graphical
+# hierarchy of all classes instead of a textual one.
+# The default value is: YES.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+GRAPHICAL_HIERARCHY    = YES
+
+# If the DIRECTORY_GRAPH tag is set to YES then doxygen will show the
+# dependencies a directory has on other directories in a graphical way. The
+# dependency relations are determined by the #include relations between the
+# files in the directories.
+# The default value is: YES.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DIRECTORY_GRAPH        = YES
+
+# The DOT_IMAGE_FORMAT tag can be used to set the image format of the images
+# generated by dot. For an explanation of the image formats see the section
+# output formats in the documentation of the dot tool (Graphviz (see:
+# http://www.graphviz.org/)).
+# Note: If you choose svg you need to set HTML_FILE_EXTENSION to xhtml in order
+# to make the SVG files visible in IE 9+ (other browsers do not have this
+# requirement).
+# Possible values are: png, png:cairo, png:cairo:cairo, png:cairo:gd, png:gd,
+# png:gd:gd, jpg, jpg:cairo, jpg:cairo:gd, jpg:gd, jpg:gd:gd, gif, gif:cairo,
+# gif:cairo:gd, gif:gd, gif:gd:gd, svg, png:gd, png:gd:gd, png:cairo,
+# png:cairo:gd, png:cairo:cairo, png:cairo:gdiplus, png:gdiplus and
+# png:gdiplus:gdiplus.
+# The default value is: png.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_IMAGE_FORMAT       = png
+
+# If DOT_IMAGE_FORMAT is set to svg, then this option can be set to YES to
+# enable generation of interactive SVG images that allow zooming and panning.
+#
+# Note that this requires a modern browser other than Internet Explorer. Tested
+# and working are Firefox, Chrome, Safari, and Opera.
+# Note: For IE 9+ you need to set HTML_FILE_EXTENSION to xhtml in order to make
+# the SVG files visible. Older versions of IE do not have SVG support.
+# The default value is: NO.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+INTERACTIVE_SVG        = NO
+
+# The DOT_PATH tag can be used to specify the path where the dot tool can be
+# found. If left blank, it is assumed the dot tool can be found in the path.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_PATH               =
+
+# The DOTFILE_DIRS tag can be used to specify one or more directories that
+# contain dot files that are included in the documentation (see the \dotfile
+# command).
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOTFILE_DIRS           =
+
+# The MSCFILE_DIRS tag can be used to specify one or more directories that
+# contain msc files that are included in the documentation (see the \mscfile
+# command).
+
+MSCFILE_DIRS           =
+
+# The DIAFILE_DIRS tag can be used to specify one or more directories that
+# contain dia files that are included in the documentation (see the \diafile
+# command).
+
+DIAFILE_DIRS           =
+
+# When using plantuml, the PLANTUML_JAR_PATH tag should be used to specify the
+# path where java can find the plantuml.jar file. If left blank, it is assumed
+# PlantUML is not used or called during a preprocessing step. Doxygen will
+# generate a warning when it encounters a \startuml command in this case and
+# will not generate output for the diagram.
+
+PLANTUML_JAR_PATH      =
+
+# When using plantuml, the PLANTUML_CFG_FILE tag can be used to specify a
+# configuration file for plantuml.
+
+PLANTUML_CFG_FILE      =
+
+# When using plantuml, the specified paths are searched for files specified by
+# the !include statement in a plantuml block.
+
+PLANTUML_INCLUDE_PATH  =
+
+# The DOT_GRAPH_MAX_NODES tag can be used to set the maximum number of nodes
+# that will be shown in the graph. If the number of nodes in a graph becomes
+# larger than this value, doxygen will truncate the graph, which is visualized
+# by representing a node as a red box. Note that doxygen if the number of direct
+# children of the root node in a graph is already larger than
+# DOT_GRAPH_MAX_NODES then the graph will not be shown at all. Also note that
+# the size of a graph can be further restricted by MAX_DOT_GRAPH_DEPTH.
+# Minimum value: 0, maximum value: 10000, default value: 50.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_GRAPH_MAX_NODES    = 50
+
+# The MAX_DOT_GRAPH_DEPTH tag can be used to set the maximum depth of the graphs
+# generated by dot. A depth value of 3 means that only nodes reachable from the
+# root by following a path via at most 3 edges will be shown. Nodes that lay
+# further from the root node will be omitted. Note that setting this option to 1
+# or 2 may greatly reduce the computation time needed for large code bases. Also
+# note that the size of a graph can be further restricted by
+# DOT_GRAPH_MAX_NODES. Using a depth of 0 means no depth restriction.
+# Minimum value: 0, maximum value: 1000, default value: 0.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+MAX_DOT_GRAPH_DEPTH    = 0
+
+# Set the DOT_TRANSPARENT tag to YES to generate images with a transparent
+# background. This is disabled by default, because dot on Windows does not seem
+# to support this out of the box.
+#
+# Warning: Depending on the platform used, enabling this option may lead to
+# badly anti-aliased labels on the edges of a graph (i.e. they become hard to
+# read).
+# The default value is: NO.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_TRANSPARENT        = NO
+
+# Set the DOT_MULTI_TARGETS tag to YES to allow dot to generate multiple output
+# files in one run (i.e. multiple -o and -T options on the command line). This
+# makes dot run faster, but since only newer versions of dot (>1.8.10) support
+# this, this feature is disabled by default.
+# The default value is: NO.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+DOT_MULTI_TARGETS      = NO
+
+# If the GENERATE_LEGEND tag is set to YES doxygen will generate a legend page
+# explaining the meaning of the various boxes and arrows in the dot generated
+# graphs.
+# The default value is: YES.
+# This tag requires that the tag HAVE_DOT is set to YES.
+
+GENERATE_LEGEND        = YES
+
+# If the DOT_CLEANUP tag is set to YES, doxygen will remove the intermediate
+# files that are used to generate the various graphs.
+#
+# Note: This setting is not only used for dot files but also for msc and
+# plantuml temporary files.
+# The default value is: YES.
+
+DOT_CLEANUP            = YES
diff --git a/examples/README.md b/examples/README.md
index 8e0959f9..f2eec750 100644
--- a/examples/README.md
+++ b/examples/README.md
@@ -7,6 +7,15 @@ languages we support (other than C++. For C++ examples see the
 At the moment we support C and C++ only, but we plan to support Rust, Python,
 and .NET wrappers, with more as demand dictates.
 
+## C++
+The best way to get started with the C++ API is to look at the
+[rego](../tools/main.cc) tool. It exercises most of the API and is a good
+starting point for understanding how to use the library.
+
+A more in-depth example which performs node matching and other more complex
+operations can be see in the [`TestCase`](../tests/test_case.cc) class from the
+test driver.
+
 ## C
 The C example is a [simple command line tool](c/main.c) that takes one or more
 Rego data, module, and input files and evaluates a query against them.
@@ -35,4 +44,4 @@ The resulting executable can be called from within the `dist` directory:
 ```bash
 cd dist
 ./bin/regoc -d examples/scalars.rego -q data.scalars.greeting
-```
+```
\ No newline at end of file
diff --git a/examples/c/main.c b/examples/c/main.c
index 56368c06..9a39fa57 100644
--- a/examples/c/main.c
+++ b/examples/c/main.c
@@ -14,9 +14,9 @@
 static struct cag_option options[] = {
   {.identifier = 'l',
    .access_letters = "l",
-   .access_name = "logging",
-   .value_name = NULL,
-   .description = "Enable logging"},
+   .access_name = "log_level",
+   .value_name = "VALUE",
+   .description = "Log level (one of 'n', 'e', 'w', 'i', 'd', 't')"},
 
   {.identifier = 'r',
    .access_letters = "r",
@@ -54,7 +54,7 @@ static struct cag_option options[] = {
  */
 struct regoc_configuration
 {
-  bool logging_enabled;
+  char log_level;
   bool use_raw_query;
   const char* data_files[MAX_DATA_FILES];
   unsigned int data_files_count;
@@ -191,7 +191,7 @@ int main(int argc, char** argv)
   char identifier;
   cag_option_context context;
   struct regoc_configuration config = {
-    .logging_enabled = false,
+    .log_level = 'n',
     .use_raw_query = false,
     .data_files_count = 0,
     .input_file = NULL,
@@ -209,7 +209,7 @@ int main(int argc, char** argv)
     switch (identifier)
     {
       case 'l':
-        config.logging_enabled = true;
+        config.log_level = cag_option_get_value(&context)[0];
         break;
 
       case 'r':
@@ -253,10 +253,6 @@ int main(int argc, char** argv)
   }
 
   rego = regoNew();
-  if (config.logging_enabled)
-  {
-    regoSetLoggingEnabled(true);
-  }
 
   for (data_index = 0; data_index < config.data_files_count; data_index++)
   {
diff --git a/examples/cpp/CMakeLists.txt b/examples/cpp/CMakeLists.txt
new file mode 100644
index 00000000..6886985a
--- /dev/null
+++ b/examples/cpp/CMakeLists.txt
@@ -0,0 +1,45 @@
+# Copyright (c) Microsoft Corporation.
+# Licensed under the MIT License.
+
+cmake_minimum_required(VERSION 3.15)
+
+include(FetchContent)
+
+project( regoc VERSION 0.1.0 LANGUAGES C CXX )
+
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+if (DEFINED ENV{REGOCPP_C_WRAPPER_REPO})
+  set(REGOCPP_C_WRAPPER_REPO $ENV{REGOCPP_C_WRAPPER_REPO})
+else ()
+  set(REGOCPP_C_WRAPPER_REPO "https://github.com/microsoft/rego-cpp/")
+endif ()
+
+if (DEFINED ENV{REGOCPP_C_WRAPPER_TAG})
+  set(REGOCPP_C_WRAPPER_TAG $ENV{REGOCPP_C_WRAPPER_TAG})
+else ()
+  set(REGOCPP_C_WRAPPER_TAG "main")
+endif()
+
+FetchContent_Declare(
+  regocpp
+  GIT_REPOSITORY ${REGOCPP_C_WRAPPER_REPO}
+  GIT_TAG        ${REGOCPP_C_WRAPPER_TAG}
+)
+
+set(CMAKE_POLICY_DEFAULT_CMP0077 NEW) 
+
+FetchContent_MakeAvailable(regocpp)
+
+add_executable(custom_builtin custom_builtin.cc)
+target_link_libraries(custom_builtin PRIVATE regocpp::rego)
+
+install(TARGETS custom_builtin DESTINATION bin)
+
+enable_testing()
+add_test(
+  NAME custom_builtin
+  COMMAND bin/custom_builtin
+  WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/dist
+)
+set_tests_properties(custom_builtin PROPERTIES PASS_REGULAR_EXPRESSION "5")
\ No newline at end of file
diff --git a/examples/cpp/CMakePresets.json b/examples/cpp/CMakePresets.json
new file mode 100644
index 00000000..49db770b
--- /dev/null
+++ b/examples/cpp/CMakePresets.json
@@ -0,0 +1,51 @@
+{
+  "version": 3,
+  "configurePresets": [
+    {
+      "name": "debug-clang",
+      "displayName": "Debug Build using clang",
+      "description": "Sets up a debug build that uses Clang",
+      "generator": "Ninja",
+      "cacheVariables": {
+        "CMAKE_BUILD_TYPE": "Debug",
+        "CMAKE_INSTALL_PREFIX": "${sourceDir}/build/dist",
+        "CMAKE_C_COMPILER": "clang",
+        "CMAKE_CXX_COMPILER": "clang++",
+        "REGOCPP_COPY_EXAMPLES": "ON"
+      }
+    },
+    {
+      "name": "debug",
+      "displayName": "Debug Build",
+      "description": "Sets up a debug build that uses the default compiler and generator",
+      "cacheVariables": {
+        "CMAKE_BUILD_TYPE": "Debug",
+        "CMAKE_INSTALL_PREFIX": "${sourceDir}/build/dist",
+        "REGOCPP_COPY_EXAMPLES": "ON"
+      }
+    },
+    {
+      "name": "release-clang",
+      "displayName": "Release Build using clang",
+      "description": "Sets up a release build that uses Clang",
+      "generator": "Ninja",
+      "cacheVariables": {
+        "CMAKE_BUILD_TYPE": "Release",
+        "CMAKE_INSTALL_PREFIX": "${sourceDir}/build/dist",
+        "CMAKE_C_COMPILER": "clang",
+        "CMAKE_CXX_COMPILER": "clang++",
+        "REGOCPP_COPY_EXAMPLES": "ON"
+      }
+    },
+    {
+      "name": "release",
+      "displayName": "Release Build",
+      "description": "Sets up a release build that uses the default compiler and generator",
+      "cacheVariables": {
+        "CMAKE_BUILD_TYPE": "Release",
+        "CMAKE_INSTALL_PREFIX": "${sourceDir}/build/dist",
+        "REGOCPP_COPY_EXAMPLES": "ON"
+      }
+    }
+  ]
+}
\ No newline at end of file
diff --git a/examples/cpp/custom_builtin.cc b/examples/cpp/custom_builtin.cc
new file mode 100644
index 00000000..2931cd42
--- /dev/null
+++ b/examples/cpp/custom_builtin.cc
@@ -0,0 +1,29 @@
+#include <rego/rego.hh>
+
+using namespace rego;
+
+Node add(const Nodes& args)
+{
+  Node a = unwrap_arg(args, UnwrapOpt(0).types({Int, Float}));
+  if(a->type() == Error){
+    return a;
+  }
+
+  Node b = unwrap_arg(args, UnwrapOpt(1).types({Int, Float}));
+  if(b->type() == Error){
+    return b;
+  }
+
+  if(a->type() == Int && b->type() == Int){
+    return scalar(get_int(a) + get_int(b));
+  }
+
+  return scalar(get_double(a) + get_double(b));
+}
+
+int main()
+{
+  Interpreter rego;
+  rego.builtins().register_builtin(BuiltInDef::create(Location("myadd"), 2, add));
+  std::cout << rego.query("myadd(2, 3)");
+}
\ No newline at end of file
diff --git a/include/rego/rego.hh b/include/rego/rego.hh
index a580de54..6e1b7296 100644
--- a/include/rego/rego.hh
+++ b/include/rego/rego.hh
@@ -3,9 +3,16 @@
 
 #pragma once
 
-#include <trieste/driver.h>
 #include "rego_c.h"
 
+#include <trieste/driver.h>
+
+/**
+ *  This namespace provides the C++ API for the library.
+ *  It includes all the token types for nodes in the AST, the well-formedness
+ *  definitions for each pass, the built-in system and custom types for
+ *  handling various kinds of data (e.g. the BigInt class).
+ */
 namespace rego
 {
   using namespace trieste;
@@ -46,11 +53,11 @@ namespace rego
   inline const auto ObjectItem = TokenDef("object-item");
   inline const auto RawString = TokenDef("raw-string", flag::print);
   inline const auto JSONString = TokenDef("STRING", flag::print);
-  inline const auto JSONInt = TokenDef("INT", flag::print);
-  inline const auto JSONFloat = TokenDef("FLOAT", flag::print);
-  inline const auto JSONTrue = TokenDef("true");
-  inline const auto JSONFalse = TokenDef("false");
-  inline const auto JSONNull = TokenDef("null");
+  inline const auto Int = TokenDef("INT", flag::print);
+  inline const auto Float = TokenDef("FLOAT", flag::print);
+  inline const auto True = TokenDef("true");
+  inline const auto False = TokenDef("false");
+  inline const auto Null = TokenDef("null");
   inline const auto Equals = TokenDef("==");
   inline const auto NotEquals = TokenDef("!=");
   inline const auto LessThan = TokenDef("<");
@@ -214,8 +221,7 @@ namespace rego
 
   using namespace wf::ops;
 
-  inline const auto wf_json =
-    JSONString | JSONInt | JSONFloat | JSONTrue | JSONFalse | JSONNull;
+  inline const auto wf_json = JSONString | Int | Float | True | False | Null;
 
   inline const auto wf_arith_op = Add | Subtract | Multiply | Divide | Modulo;
 
@@ -351,7 +357,7 @@ namespace rego
   inline const auto wf_pass_rules =
     wf_pass_elses
     | (Policy <<= Rule++)
-    | (Rule <<= (Default >>= JSONTrue | JSONFalse) * RuleHead * (Body >>= UnifyBody | Empty) * ElseSeq)
+    | (Rule <<= (Default >>= True | False) * RuleHead * (Body >>= UnifyBody | Empty) * ElseSeq)
     | (RuleHead <<= RuleRef * (RuleHeadType >>= RuleHeadComp | RuleHeadFunc | RuleHeadSet | RuleHeadObj))
     | (RuleRef <<= (Var | Array | Dot)++[1])
     | (ElseSeq <<= Else++)
@@ -424,7 +430,7 @@ namespace rego
     | (Keyword <<= Var)[Var]
     | (Package <<= Ref)
     | (Policy <<= Rule++)
-    | (Rule <<= (Default >>= JSONTrue | JSONFalse) * RuleHead * (Body >>= UnifyBody | Empty) * ElseSeq)
+    | (Rule <<= (Default >>= True | False) * RuleHead * (Body >>= UnifyBody | Empty) * ElseSeq)
     | (RuleHead <<= RuleRef * (RuleHeadType >>= RuleHeadComp | RuleHeadFunc | RuleHeadSet | RuleHeadObj))
     | (RuleRef <<= Ref | Var)
     | (ElseSeq <<= Else++)
@@ -454,7 +460,7 @@ namespace rego
     | (RefArgSeq <<= (RefArgDot | RefArgBrack)++)
     | (RefArgDot <<= Var)
     | (RefArgBrack <<= Scalar | Var | Object | Array | Set | Expr)
-    | (Scalar <<= String | JSONInt | JSONFloat | JSONTrue | JSONFalse | JSONNull)
+    | (Scalar <<= String | Int | Float | True | False | Null)
     | (String <<= JSONString | RawString)
     | (Array <<= Expr++)
     | (Set <<= Expr++)
@@ -470,7 +476,7 @@ namespace rego
   // clang-format off
   inline const auto wf_pass_strings =
     wf_pass_structure
-    | (Scalar <<= JSONString | JSONInt | JSONFloat | JSONTrue | JSONFalse | JSONNull)
+    | (Scalar <<= JSONString | Int | Float | True | False | Null)
     ;
   // clang-format on
 
@@ -505,8 +511,8 @@ namespace rego
     wf_pass_lift_refheads
     | (Module <<= Package * Policy)
     | (Policy <<= (Import | RuleComp | RuleFunc | RuleSet | RuleObj)++)
-    | (RuleComp <<= Var * (Body >>= UnifyBody | Empty) * (Val >>= UnifyBody | Term) * (Idx >>= JSONInt))[Var]
-    | (RuleFunc <<= Var * RuleArgs * (Body >>= UnifyBody | Empty) * (Val >>= UnifyBody | Term) * (Idx >>= JSONInt))[Var]
+    | (RuleComp <<= Var * (Body >>= UnifyBody | Empty) * (Val >>= UnifyBody | Term) * (Idx >>= Int))[Var]
+    | (RuleFunc <<= Var * RuleArgs * (Body >>= UnifyBody | Empty) * (Val >>= UnifyBody | Term) * (Idx >>= Int))[Var]
     | (RuleSet <<= Var * (Body >>= UnifyBody | Empty) * (Val >>= Expr | Term))[Var]
     | (RuleObj <<= Var * (Body >>= UnifyBody | Empty) * (Key >>= Expr | Term) * (Val >>= Expr | Term))[Var]
     | (UnifyBody <<= (Local | Literal | LiteralWith | LiteralEnum)++[1])
@@ -519,7 +525,7 @@ namespace rego
     | (ArrayCompr <<= Expr * (Body >>= NestedBody))
     | (SetCompr <<= Expr * (Body >>= NestedBody))
     | (RefTerm <<= Ref | Var)
-    | (NumTerm <<= JSONInt | JSONFloat)
+    | (NumTerm <<= Int | Float)
     | (RefArgBrack <<= RefTerm | Scalar | Object | Array | Set | Expr)
     | (Expr <<= wf_symbols_exprs++[1])
     | (Import <<= Var * Ref)[Var]
@@ -549,8 +555,8 @@ namespace rego
   // clang-format off
   inline const auto wf_pass_constants =
     wf_pass_lift_query
-    | (RuleComp <<= Var * (Body >>= UnifyBody | Empty) * (Val >>= UnifyBody | DataTerm) * (Idx >>= JSONInt))[Var]
-    | (RuleFunc <<= Var * RuleArgs * (Body >>= UnifyBody | Empty) * (Val >>= UnifyBody | DataTerm) * (Idx >>= JSONInt))[Var]
+    | (RuleComp <<= Var * (Body >>= UnifyBody | Empty) * (Val >>= UnifyBody | DataTerm) * (Idx >>= Int))[Var]
+    | (RuleFunc <<= Var * RuleArgs * (Body >>= UnifyBody | Empty) * (Val >>= UnifyBody | DataTerm) * (Idx >>= Int))[Var]
     | (RuleSet <<= Var * (Body >>= UnifyBody | Empty) * (Val >>= Expr | DataTerm))[Var]
     | (RuleObj <<= Var * (Body >>= UnifyBody | Empty) * (Key >>= Expr | DataTerm) * (Val >>= Expr | DataTerm))[Var]
     ;
@@ -754,8 +760,8 @@ namespace rego
     | (Object <<= ObjectItem++)
     | (ObjectItem <<= (Key >>= Term) * (Val >>= Term))
     | (DataItem <<= Key * (Val >>= DataModule | Term))[Key]
-    | (RuleComp <<= Var * (Body >>= UnifyBody | Empty) * (Val >>= UnifyBody | Term) * (Idx >>= JSONInt))[Var]
-    | (RuleFunc <<= Var * RuleArgs * (Body >>= UnifyBody | Empty) * (Val >>= UnifyBody | Term) * (Idx >>= JSONInt))[Var]
+    | (RuleComp <<= Var * (Body >>= UnifyBody | Empty) * (Val >>= UnifyBody | Term) * (Idx >>= Int))[Var]
+    | (RuleFunc <<= Var * RuleArgs * (Body >>= UnifyBody | Empty) * (Val >>= UnifyBody | Term) * (Idx >>= Int))[Var]
     | (RuleSet <<= Var * (Body >>= UnifyBody | Empty) * (Val >>= UnifyBody | Term))[Var]
     | (RuleObj <<= Var * (Body >>= UnifyBody | Empty) * (Val >>= UnifyBody | Term))[Var]
     ;
@@ -778,49 +784,11 @@ namespace rego
   // clang-format on
 
   struct BuiltInDef;
+  /** A pointer to a BuiltInDef.*/
   using BuiltIn = std::shared_ptr<BuiltInDef>;
-  using BuiltInBehavior = Node (*)(const Nodes&);
-
-  const std::size_t AnyArity = std::numeric_limits<std::size_t>::max();
-  struct BuiltInDef
-  {
-    Location name;
-    std::size_t arity;
-    BuiltInBehavior behavior;
-    static BuiltIn create(
-      const Location& name, std::size_t arity, BuiltInBehavior behavior);
-  };
 
-  class BuiltIns
-  {
-  public:
-    BuiltIns() noexcept;
-    bool is_builtin(const Location& name) const;
-    Node call(const Location& name, const Nodes& args) const;
-    BuiltIns& register_builtin(const BuiltIn& built_in);
-    const BuiltIn& at(const Location& name) const;
-    bool strict_errors() const;
-    BuiltIns& strict_errors(bool strict_errors);
-
-    template <typename T>
-    BuiltIns& register_builtins(const T& built_ins)
-    {
-      for (auto& built_in : built_ins)
-      {
-        register_builtin(built_in);
-      }
-
-      return *this;
-    }
-
-    BuiltIns& register_standard_builtins();
-    std::map<Location, BuiltIn>::const_iterator begin() const;
-    std::map<Location, BuiltIn>::const_iterator end() const;
-
-  private:
-    std::map<Location, BuiltIn> m_builtins;
-    bool m_strict_errors;
-  };
+  /** The function pointer to the behavior of the built-in. */
+  using BuiltInBehavior = Node (*)(const Nodes&);
 
   /**
    * This is a basic, non-optimized implementation of a big integer using
@@ -891,6 +859,423 @@ namespace rego
     static Location One;
   };
 
+  /**
+   * Result of unwrapping a node.
+   */
+  struct UnwrapResult
+  {
+    /** The unwrapped argument or nullptr (if unsuccessful). */
+    Node node;
+
+    /** True if the argument was unwrapped successfully. */
+    bool success;
+  };
+
+  /**
+   * This struct provides options for unwrapping an argument and producing
+   * an error message.
+   *
+   * The act of unwrapping a node is the process of testing whether a node
+   * or one of its direct descendents is of one or more types. So, for example,
+   * the following nodes:
+   *
+   * ```
+   * (term (scalar (int 5)))
+   * (scalar (int 5))
+   * (int 5)
+   * ```
+   *
+   * Would all be successfully unwrapped as `(int 5)` if the type JSONInt was
+   * specified. However, if Float was specified, the result would be an
+   * error node.
+   */
+  class UnwrapOpt
+  {
+  public:
+    /**
+     * Construct an UnwrapOpt.
+     *
+     * @param index The index of the argument to unwrap.
+     */
+    UnwrapOpt(std::size_t index);
+
+    /**
+     * Whether the statement indicating what was received instead
+     * of the expect type should be excluded.
+     */
+    bool exclude_got() const;
+    UnwrapOpt& exclude_got(bool exclude_got);
+
+    /**
+     * Whether to specify in the error message which kind of number
+     * was received (i.e. integer or floating point)
+     */
+    bool specify_number() const;
+    UnwrapOpt& specify_number(bool specify_number);
+
+    /**
+     * The error code for the error message.
+     *
+     * Default value if omitted is EvalTypeError.
+     */
+    const std::string& code() const;
+    UnwrapOpt& code(const std::string& value);
+
+    /**
+     * The error preamble.
+     *
+     * If omitted, a default preamble will be constructed
+     * from the operation metadata in the form "operand <i> must be <t>".
+     */
+    const std::string& pre() const;
+    UnwrapOpt& pre(const std::string& value);
+
+    /**
+     * The full error message.
+     *
+     * If this is set, no message will be generated and instead
+     * this will be returned verbatim.
+     */
+    const std::string& message() const;
+    UnwrapOpt& message(const std::string& value);
+
+    /**
+     * The name of the function.
+     *
+     * If provide, will be a prefix on the message as "<func-name>:"
+     */
+    const std::string& func() const;
+    UnwrapOpt& func(const std::string& value);
+
+    /**
+     * The types to match against.
+     *
+     * The operand must be one of the provided types or else an
+     * error node will be return.
+     */
+    const std::vector<Token>& types() const;
+    UnwrapOpt& types(const std::vector<Token>& value);
+
+    /**
+     * The singular type to match against.
+     */
+    const Token& type() const;
+    UnwrapOpt& type(const Token& value);
+
+    /**
+     * Unwraps an argument from the provided vector of nodes.
+     *
+     * @param args The vector of nodes to unwrap from.
+     * @return The unwrapped argument or an appropriate error node.
+     */
+    Node unwrap(const Nodes& args) const;
+
+  private:
+    bool m_exclude_got;
+    bool m_specify_number;
+    std::string m_code;
+    std::string m_prefix;
+    std::string m_message;
+    std::string m_func;
+    std::vector<Token> m_types;
+    std::size_t m_index;
+  };
+
+  /**
+   * Unwraps an argument from the provided vector of nodes.
+   *
+   * @param args The vector of nodes to unwrap from.
+   * @param options The options for unwrapping.
+   * @return The unwrapped argument or an appropriate error node.
+   */
+  Node unwrap_arg(const Nodes& args, const UnwrapOpt& options);
+
+  /**
+   * Attempts to unwrap an argument to one of the specified types.
+   *
+   * @param term The term to unwrap.
+   * @param types The acceptable types.
+   * @return An unwrap result.
+   */
+  UnwrapResult unwrap(const Node& term, const std::set<Token>& types);
+
+  /**
+   * Extracts the value of a node as an integer.
+   *
+   * @param node The node to extract from.
+   * @return The integer value of the node.
+   */
+  BigInt get_int(const Node& node);
+
+  /**
+   * Extracts the value of a node as a double.
+   *
+   * @param node The node to extract from.
+   * @return The double value of the node.
+   */
+  double get_double(const Node& node);
+
+  /**
+   * Extracts the value of a node as a string.
+   *
+   * The resulting string will have any enclosing quotes removed.
+   *
+   * @param node The node to extract from.
+   * @return The string value of the node.
+   */
+  std::string get_string(const Node& node);
+
+  /**
+   * Extracts the value of a node as a boolean.
+   *
+   * @param node The node to extract from.
+   * @return The boolean value of the node.
+   */
+  bool get_bool(const Node& node);
+
+  /**
+   * Converts the value to a scalar node.
+   *
+   * @param value The value to convert.
+   * @return The scalar node (scalar (INT <value>)))
+   */
+  Node scalar(BigInt value);
+
+  /**
+   * Converts the value to a scalar node.
+   *
+   * @param value The value to convert.
+   * @return The scalar node (scalar (FLOAT <value>)))
+   */
+  Node scalar(double value);
+
+  /**
+   * Converts the value to a scalar node.
+   *
+   * @param value The value to convert.
+   * @return The scalar node (scalar (TRUE|FALSE)))
+   */
+  Node scalar(bool value);
+
+  /**
+   * Converts the value to a scalar node.
+   *
+   * @param value The value to convert.
+   * @return The scalar node (scalar (STRING <value>)))
+   */
+  Node scalar(const char* value);
+
+  /**
+   * Converts the value to a scalar node.
+   *
+   * @param value The value to convert.
+   * @return The scalar node (scalar (STRING <value>)))
+   */
+  Node scalar(const std::string& value);
+
+  /**
+   * Converts the value to a scalar node.
+   *
+   * @param value The value to convert.
+   * @return The scalar node (scalar (NULL)))
+   */
+  Node scalar();
+
+  /**
+   * Converts the key and val terms to an object item.
+   *
+   * @param key_term The key term.
+   * @param val_term The value term.
+   * @return The object item node (object_item (key_term) (val_term))
+   */
+  Node object_item(const Node& key_term, const Node& val_term);
+
+  /**
+   * Converts the value to an object node.
+   *
+   * @param object_items The object items of the object
+   * @return The object node (object (object_item) (object_item) ...)
+   */
+  Node object(const Nodes& object_items);
+
+  /**
+   * Converts the value to an array node.
+   *
+   * @param array_members The members of the array.
+   * @return The array node (array (term) (term) ...)
+   */
+  Node array(const Nodes& array_members);
+
+  /**
+   * Converts the value to a set node.
+   *
+   * @param set_members The members of the set.
+   * @return The set node (set (term) (term) ...)
+   */
+  Node set(const Nodes& set_members);
+
+  /** This constant indicates that a built-in can receive any number of
+   * arguments. */
+  const std::size_t AnyArity = std::numeric_limits<std::size_t>::max();
+
+  /**
+   * Struct which defines a built-in function.
+   *
+   * You can extend Rego by registering your own built-ins. A built-in is a
+   * function which is called by Rego during evaluation. Built-ins are called
+   * with a vector of Nodes, and return a Node. The vector of Nodes contains the
+   * arguments passed to the built-in. The Node returned by the built-in is the
+   * result of the built-in's evaluation.
+   *
+   * Here is an example built-in which performs addition:
+   *
+   * ```cpp
+   * Node add(const Nodes& args)
+   * {
+   *   Node a = unwrap_arg(args, UnwrapOpt(0).types({Int, Float}));
+   *   if(a.type() == Error){
+   *     return a;
+   *   }
+   *
+   *   Node b = unwrap_arg(args, UnwrapOpt(1).types({Int, Float}));
+   *   if(b.type() == Error){
+   *    return b;
+   *   }
+   *
+   *   if(a.type() == Int && b.type() == Int)
+   *   {
+   *     return scalar(get_int(a) + get_int(b));
+   *   }
+   *
+   *   return scalar(get_double(a) + get_double(b));
+   * }
+   * ```
+   *
+   * Note that there are several helper methods and objects to aid in
+   * writing managing nodes and wrapping/unwrapping them into basic
+   * types. Once a method like the above has been written, use
+   * BuiltInDef::create following way:
+   * ```cpp
+   * builtins.register_builtin(BuiltInDef::create(Location("add"), 2, add))
+   * ```
+   *
+   * Then, during evaluation, any call to the built-in `add` will be
+   * handled by the `add` function.
+   */
+  struct BuiltInDef
+  {
+    /** The name used to match against expression calls in the rego program. */
+    Location name;
+    /**
+     * The number of expected arguments.
+     *
+     * If any number of arguments can be provided, use the constant AnyArity.
+     */
+    std::size_t arity;
+
+    /** The function which will be called when the built-in is evaluated. */
+    BuiltInBehavior behavior;
+
+    /**
+     * Creates a new built-in.
+     *
+     * BuiltIn is a pointer to a BuiltInDef.
+     *
+     * @param name The name of the built-in.
+     * @param arity The number of arguments expected by the built-in.
+     * @param behavior The function which will be called when the built-in is
+     * evaluated.
+     * @return The built-in.
+     */
+    static BuiltIn create(
+      const Location& name, std::size_t arity, BuiltInBehavior behavior);
+  };
+
+  /**
+   * Manages the set of builtins used by an interpreter to resolve built-in
+   * calls.
+   */
+  class BuiltIns
+  {
+  public:
+    /** Constructor. */
+    BuiltIns() noexcept;
+
+    /**
+     * Determines whether the provided name refers to a built-in.
+     *
+     * @param name The name to check.
+     * @return True if the name refers to a built-in, otherwise false.
+     */
+    bool is_builtin(const Location& name) const;
+
+    /**
+     * Calls the built-in with the provided name and arguments.
+     *
+     * @param name The name of the built-in to call.
+     * @param args The arguments to pass to the built-in.
+     * @return The result of the built-in call.
+     */
+    Node call(const Location& name, const Nodes& args) const;
+
+    /**
+     * Registers a built-in.
+     *
+     * @param built_in The built-in to register.
+     */
+    BuiltIns& register_builtin(const BuiltIn& built_in);
+
+    /**
+     * Gets the built-in with the provided name.
+     */
+    const BuiltIn& at(const Location& name) const;
+
+    /**
+     * Whether to throw built-in errors.
+     *
+     * If true, built-in errors will be thrown as exceptions. If false,
+     * built-in errors will result in Undefined nodes.
+     */
+    bool strict_errors() const;
+    BuiltIns& strict_errors(bool strict_errors);
+
+    /**
+     * Registers a set of built-ins.
+     *
+     * @param built_ins The built-ins to register.
+     */
+    template <typename T>
+    BuiltIns& register_builtins(const T& built_ins)
+    {
+      for (auto& built_in : built_ins)
+      {
+        register_builtin(built_in);
+      }
+
+      return *this;
+    }
+
+    /**
+     * This registers the "standard library" of built-ins.
+     *
+     * There are a number of built-ins which are provided by default. These
+     * built-ins are those documented
+     * <a
+     * href="https://www.openpolicyagent.org/docs/latest/policy-reference/#built-in-functions">here</a>.
+     *
+     * rego-cpp supports the following built-ins as standard:
+     *
+     */
+    BuiltIns& register_standard_builtins();
+
+    std::map<Location, BuiltIn>::const_iterator begin() const;
+    std::map<Location, BuiltIn>::const_iterator end() const;
+
+  private:
+    std::map<Location, BuiltIn> m_builtins;
+    bool m_strict_errors;
+  };
+
   const std::string EvalTypeError = "eval_type_error";
   const std::string EvalBuiltInError = "eval_builtin_error";
   const std::string RegoTypeError = "rego_type_error";
@@ -898,49 +1283,263 @@ namespace rego
   const std::string WellFormedError = "wellformed_error";
   const std::string RuntimeError = "runtime_error";
 
+  /**
+   * Generates an error node.
+   *
+   * @param r The range of nodes over which the error occurred.
+   * @param msg The error message.
+   * @param code The error code.
+   */
   Node err(
     NodeRange& r,
     const std::string& msg,
     const std::string& code = WellFormedError);
 
+  /**
+   * Generates an error node.
+   *
+   * @param node The node for which the error occurred.
+   * @param msg The error message.
+   * @param code The error code.
+   */
   Node err(
     Node node,
     const std::string& msg,
     const std::string& code = WellFormedError);
 
+  using PassCheck = std::tuple<std::string, Pass, const wf::Wellformed*>;
+
+  /**
+   * Creates the parser object, which turns a document into tokens.
+   *
+   * @return The parser.
+   */
   Parse parser();
+
+  /**
+   * Creates a test driver.
+   *
+   * The test driver performs probabilstic testing of the complication. For each
+   * pass it generates random AST outputs depending on the well-formed
+   * expression of the input, runs them through the pass logic, and then checks
+   * it against the wf expression for the output.
+   *
+   * @param builtins The built-ins to use.
+   * @return The driver.
+   */
   Driver& driver(const BuiltIns& builtins);
-  using PassCheck = std::tuple<std::string, Pass, const wf::Wellformed*>;
-  std::vector<PassCheck> passes(const BuiltIns& builtins);
+
+  /**
+   * Returns a node representing the version of the library.
+   *
+   * The resulting node will be an object containing:
+   * - The Git commit hash ("commit")
+   * - The library version ("regocpp_version")
+   * - The supported OPA Rego version ("version")
+   * - The environment variables ("env")
+   */
   Node version();
 
+  /** Converts a node to JSON.
+   *
+   * @param node The node to convert.
+   * @param sort Whether to sort the keys of a JSON object or the values in a
+   * set.
+   * @param set_as_array Whether to represent a set using array notation.
+   */
   std::string to_json(
-    const trieste::Node& node, bool sort = false, bool rego_set = true);
-  void set_logging_enabled(bool enabled);
+    const trieste::Node& node, bool sort = false, bool set_as_array = false);
 
-class Interpreter
+  /**
+   * The logging level.
+   */
+  enum class LogLevel : char
+  {
+    None = REGO_LOG_LEVEL_NONE,
+    Error = REGO_LOG_LEVEL_ERROR,
+    Warn = REGO_LOG_LEVEL_WARN,
+    Info = REGO_LOG_LEVEL_INFO,
+    Debug = REGO_LOG_LEVEL_DEBUG,
+    Trace = REGO_LOG_LEVEL_TRACE,
+  };
+
+  /**
+   * Sets the logging level for the library.
+   *
+   * @param level The logging level.
+   */
+  void set_log_level(LogLevel level);
+
+  /**
+   * This class forms the main interface to the Rego library.
+   *
+   * You can use it to assemble and then execute queries, for example:
+   *
+   * ```cpp
+   * Interpreter rego;
+   * rego.add_module_file("objects.rego");
+   * rego.add_data_json_file("data0.json");
+   * rego.add_data_json_file("data1.json");
+   * rego.add_input_json_file("input0.json");
+   * std::cout << rego.query("[data.one, input.b, data.objects.sites[1]]") <<
+   * std::endl;
+   * ```
+   */
+  class Interpreter
   {
   public:
+    /**
+     * Constructor.
+     *
+     * Pushes the default WF context.
+     */
     Interpreter();
+
+    /**
+     * Destructor.
+     *
+     * Pops the default WF context.
+     */
     ~Interpreter();
+
+    /**
+     * Adds a module (i.e. virtual document) file to the interpreter.
+     *
+     * This is the same as calling Interpreter::add_module with the contents of
+     * the file.
+     *
+     * @param path The path to the module file.
+     */
     void add_module_file(const std::filesystem::path& path);
+
+    /**
+     * Adds a module (i.e. virtual document) to the interpreter.
+     *
+     * The module will be parsed and added to the interpreter's module sequence.
+     *
+     * @param name The name of the module.
+     * @param contents The contents of the module.
+     */
     void add_module(const std::string& name, const std::string& contents);
+
+    /**
+     * Adds a base document to the interpreter.
+     *
+     * This is the same as calling Interpreter::add_data_json with the contents
+     * of the file.
+     *
+     * @param module The module to add.
+     */
     void add_data_json_file(const std::filesystem::path& path);
+
+    /**
+     * Adds a base document to the interpreter.
+     *
+     * The document must contain a single JSON-encoded object, and will be
+     * parsed and added to the interpreter's data sequence.
+     *
+     * @param json The contents of the document.
+     */
     void add_data_json(const std::string& json);
+
+    /**
+     * Adds a base document to the interpreter.
+     *
+     * Adds an AST node directly to the interpreter's data sequence. Use with
+     * caution.
+     *
+     * @param node The contents of the document.
+     */
     void add_data(const Node& node);
+
+    /**
+     * Sets the input document to the interpreter.
+     *
+     * This is the same as calling Interpreter::add_input_json with the contents
+     * of the file.
+     *
+     * @param path The path to the input file.
+     */
     void set_input_json_file(const std::filesystem::path& path);
+
+    /**
+     * Sets the input document to the interpreter.
+     *
+     * The document must contain a single JSON-encoded value, and will be parsed
+     * and set as the interpreter's input. This can be performed multiple times
+     * and will affect the result of any subsequent queries.
+     *
+     * @param json The contents of the document.
+     */
     void set_input_json(const std::string& json);
+
+    /**
+     * Sets the input document to the interpreter.
+     *
+     * Sets an AST node directly as the interpreter's input. Use with
+     * caution.
+     *
+     * @param node The contents of the document.
+     */
     void set_input(const Node& node);
+
+    /**
+     * Executes a query against the interpreter.
+     *
+     * This method calls Interpreter::raw_query and then converts it into a
+     * human-readable string.
+     *
+     * @param query_expr The query expression.
+     * @return The result of the query.
+     */
     std::string query(const std::string& query_expr) const;
+
+    /**
+     * Executes a query against the interpreter.
+     *
+     * The query expression must be a valid Rego query expression. The result
+     * will be an AST node representing the result, which will either be a
+     * list of bindings and terms, or an error sequence.
+     *
+     * @param query_expr The query expression.
+     * @return The result of the query.
+     */
     Node raw_query(const std::string& query_expr) const;
+
+    /**
+     * The path to the debug directory.
+     *
+     * If set, then (when in debug mode) the interpreter will output
+     * intermediary ASTs after each compiler pass to the debug directory. If the
+     * directory does not exist, it will be created.
+     */
     Interpreter& debug_path(const std::filesystem::path& prefix);
     const std::filesystem::path& debug_path() const;
+
+    /**
+     * Whether debug mode is enabled.
+     *
+     * If true, then the interpreter will output intermediary ASTs after each
+     * compiler pass to the debug directory set via Interpreter::debug_path.
+     */
     Interpreter& debug_enabled(bool enabled);
     bool debug_enabled() const;
+
+    /**
+     * Whether well-formed checks are enabled.
+     *
+     * If true, then the interpreter will perform well-formedness checks after
+     * each compiler pass using the well-formedness definitions.
+     */
     Interpreter& well_formed_checks_enabled(bool enabled);
     bool well_formed_checks_enabled() const;
-    Interpreter& executable(const std::filesystem::path& path);
-    const std::filesystem::path& executable() const;
+
+    /**
+     * The built-ins used by the interpreter.
+     *
+     * This object can be used to register custom built-ins created using
+     * BuiltInDef::create.
+     */
     BuiltIns& builtins();
     const BuiltIns& builtins() const;
 
diff --git a/include/rego/rego_c.h b/include/rego/rego_c.h
index c265832e..55f0e0cb 100644
--- a/include/rego/rego_c.h
+++ b/include/rego/rego_c.h
@@ -1,6 +1,8 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
+/** @file */
+
 #ifndef _REGO_C_H_
 #define _REGO_C_H_
 
@@ -43,47 +45,416 @@ typedef unsigned int regoSize;
 
 #define REGO_NODE_INTERNAL 1999
 
+// log levels
+#define REGO_LOG_LEVEL_NONE 0
+#define REGO_LOG_LEVEL_ERROR 1
+#define REGO_LOG_LEVEL_WARN 2
+#define REGO_LOG_LEVEL_INFO 3
+#define REGO_LOG_LEVEL_DEBUG 4
+#define REGO_LOG_LEVEL_TRACE 5
+
 #ifdef __cplusplus
 extern "C"
 {
 #endif
-  // Interpreter functions
-  void regoSetLoggingEnabled(regoBoolean enabled);
+  ////////////////////////////////////////
+  // ----- Interpreter functions ------ //
+  ////////////////////////////////////////
+
+  /**
+   * Sets the level of logging.
+   *
+   * This setting controls the amount of logging that will be output to stdout.
+   * The default level is REGO_LOG_LEVEL_NONE.
+   *
+   * @param level One of the following values: REGO_LOG_LEVEL_NONE,
+   *              REGO_LOG_LEVEL_ERROR, REGO_LOG_LEVEL_WARN,
+   *              REGO_LOG_LEVEL_INFO, REGO_LOG_LEVEL_DEBUG,
+   *              REGO_LOG_LEVEL_TRACE.
+   */
+  void regoSetLogLevel(regoEnum level);
+
+  /**
+   * Allocates and initializes a new Rego interpreter.
+   *
+   * The caller is responsible for freeing the interpreter with regoFree.
+   *
+   * @return A pointer to the new interpreter.
+   */
   regoInterpreter* regoNew();
+
+  /**
+   * Frees a Rego interpreter.
+   *
+   * This pointer must have been allocated with regoNew.
+   *
+   * @param rego The interpreter to free.
+   */
   void regoFree(regoInterpreter* rego);
+
+  /**
+   * Adds a module (e.g. virtual document) from the file at the
+   * specified path.
+   *
+   * If an error code is returned, more error information can be
+   * obtained by calling regoGetError.
+   *
+   * @param rego The interpreter.
+   * @param path The path to the policy file.
+   * @return REGO_OK if successful, REGO_ERROR otherwise.
+   */
   regoEnum regoAddModuleFile(regoInterpreter* rego, const char* path);
+
+  /**
+   * Adds a module (e.g. virtual document) from the specified string.
+   *
+   * If an error code is returned, more error information can be
+   * obtained by calling regoGetError.
+   *
+   * @param rego The interpreter.
+   * @param name The name of the module.
+   * @param contents The contents of the module.
+   * @return REGO_OK if successful, REGO_ERROR otherwise.
+   */
   regoEnum regoAddModule(
     regoInterpreter* rego, const char* name, const char* contents);
+
+  /**
+   * Adds a base document from the file at the specified path.
+   *
+   * The file should contain a single JSON object. The object will be
+   * parsed and merged with the interpreter's base document.
+   *
+   * If an error code is returned, more error information can be
+   * obtained by calling regoGetError.
+   *
+   * @param rego The interpreter.
+   * @param path The path to the JSON file.
+   * @return REGO_OK if successful, REGO_ERROR otherwise.
+   */
   regoEnum regoAddDataJSONFile(regoInterpreter* rego, const char* path);
+
+  /**
+   * Adds a base document from the specified string.
+   *
+   * The string should contain a single JSON object. The object will be
+   * parsed and merged with the interpreter's base document.
+   *
+   * If an error code is returned, more error information can be
+   * obtained by calling regoGetError.
+   *
+   * @param rego The interpreter.
+   * @param contents The contents of the JSON object.
+   * @return REGO_OK if successful, REGO_ERROR otherwise.
+   */
   regoEnum regoAddDataJSON(regoInterpreter* rego, const char* contents);
+
+  /**
+   * Sets the current input document from the file at the specified path.
+   *
+   * The file should contain a single JSON value. The value will be
+   * parsed and set as the interpreter's input document.
+   *
+   * If an error code is returned, more error information can be
+   * obtained by calling regoGetError.
+   *
+   * @param rego The interpreter.
+   * @param path The path to the JSON file.
+   * @return REGO_OK if successful, REGO_ERROR otherwise.
+   */
   regoEnum regoSetInputJSONFile(regoInterpreter* rego, const char* path);
+
+  /**
+   * Sets the current input document from the specified string.
+   *
+   * The string should contain a single JSON value. The value will be
+   * parsed and set as the interpreter's input document.
+   *
+   * If an error code is returned, more error information can be
+   * obtained by calling regoGetError.
+   *
+   * @param rego The interpreter.
+   * @param contents The contents of the JSON value.
+   * @return REGO_OK if successful, REGO_ERROR otherwise.
+   */
   regoEnum regoSetInputJSON(regoInterpreter* rego, const char* contents);
+
+  /**
+   * Sets the debug mode of the interpreter.
+   *
+   * When debug mode is enabled, the interpreter will output intermediary
+   * ASTs after each compiler pass to the debug directory and output pass
+   * information to stdout. This is mostly useful for creating reports for
+   * compiler issues, but can also be of use in understanding why a policy is
+   * invalid or is behaving unexpectedly.
+   *
+   * @param rego The interpreter.
+   * @param enabled Whether debug mode should be enabled.
+   */
   void regoSetDebugEnabled(regoInterpreter* rego, regoBoolean enabled);
+
+  /**
+   * Gets the debug mode of the interpreter.
+   *
+   * @param rego The interpreter.
+   * @return Whether debug mode is enabled.
+   */
   regoBoolean regoGetDebugEnabled(regoInterpreter* rego);
+
+  /**
+   * Sets the path to the debug directory.
+   *
+   * If set, then (when in debug mode) the interpreter will output intermediary
+   * ASTs after each compiler pass to the debug directory. If the directory does
+   * not exist, it will be created.
+   *
+   * If an error code is returned, more error information can be
+   * obtained by calling regoGetError.
+   *
+   * @param rego The interpreter.
+   * @param path The path to the debug directory.
+   * @return REGO_OK if successful, REGO_ERROR otherwise.
+   */
   regoEnum regoSetDebugPath(regoInterpreter* rego, const char* path);
+
+  /**
+   * Sets whether to perform well-formed checks after each compiler pass.
+   *
+   * The interpreter has a set of well-formness definitions which indicate the
+   * expected form of the AST before and after each compiler pass. This setting
+   * determines whether the interpreter will perform these intermediary checks.
+   *
+   * @param rego The interpreter.
+   * @param enabled Whether well-formed checks should be enabled.
+   */
   void regoSetWellFormedChecksEnabled(
     regoInterpreter* rego, regoBoolean enabled);
+
+  /**
+   * Gets whether well-formed checks are enabled.
+   *
+   * @param rego The interpreter.
+   * @return Whether well-formed checks are enabled.
+   */
   regoBoolean regoGetWellFormedChecksEnabled(regoInterpreter* rego);
+
+  /**
+   * Performs a query against the current base and virtual documents.
+   *
+   * The query expression should be a Rego query. The output of the query
+   * will be returned as a regoOutput object. The caller is responsible for
+   * freeing the output object with regoFreeOutput.
+   *
+   * @param rego The interpreter.
+   * @param query_expr The query expression.
+   * @return The output of the query.
+   */
   regoOutput* regoQuery(regoInterpreter* rego, const char* query_expr);
+
+  /**
+   * Sets whether the built-ins should throw errors.
+   *
+   * When strict built-in errors are enabled, built-in functions will throw
+   * errors when they encounter invalid input. When disabled, built-in
+   * functions will return undefined when they encounter invalid input.
+   *
+   * @param rego The interpreter.
+   * @param enabled Whether strict built-in errors should be enabled.
+   */
   void regoSetStrictBuiltInErrors(regoInterpreter* rego, regoBoolean enabled);
+
+  /**
+   * Gets whether strict built-in errors are enabled.
+   *
+   * @param rego The interpreter.
+   * @return Whether strict built-in errors are enabled.
+   */
   regoBoolean regoGetStrictBuiltInErrors(regoInterpreter* rego);
+
+  /**
+   * Returns the most recently thrown error.
+   *
+   * If an error code is returned from an interface function, more error
+   * information can be obtained by calling this function.
+   *
+   * @param rego The interpreter.
+   * @return The error message.
+   */
   const char* regoGetError(regoInterpreter* rego);
 
-  // Output functions
+  ////////////////////////////////////////
+  // -------- Output functions -------- //
+  ////////////////////////////////////////
+
+  /**
+   * Returns whether the output is ok.
+   *
+   * If the output resulted in a valid query result, then this function will
+   * return true. Otherwise, it will return false, indicating that the
+   * output contains an error sequence.
+   *
+   * @param output The output.
+   * @return Whether the output is ok.
+   */
   regoBoolean regoOutputOk(regoOutput* output);
+
+  /**
+   * Returns the node containing the output of the query.
+   *
+   * This will either be a node which contains sequence of terms and/or
+   * bindings, or an error sequence.
+   *
+   * @param output The output.
+   * @return The output node.
+   */
   regoNode* regoOutputNode(regoOutput* output);
+
+  /**
+   * Returns the bound value for a given variable name.
+   *
+   * If the variable is not bound, then this function will return NULL.
+   *
+   * @param output The output.
+   * @param name The variable name.
+   * @return The bound value (or NULL if the variable was not bound)
+   */
   regoNode* regoOutputBinding(regoOutput* output, const char* name);
+
+  /**
+   * Returns the output represented as a human-readable string.
+   *
+   * @param output The output.
+   * @return The output string.
+   */
   const char* regoOutputString(regoOutput* output);
+
+  /**
+   * Frees a Rego output.
+   *
+   * This pointer must have been allocated with regoQuery.
+   *
+   * @param output The output to free.
+   */
   void regoFreeOutput(regoOutput* output);
 
-  // Node functions
+  ////////////////////////////////////////
+  // --------- Node functions --------- //
+  ////////////////////////////////////////
+
+  // clang-format off
+
+  /**
+   * Returns an enumeration value indicating the nodes type.
+   *
+   * This type will be one of the following values:
+   *
+   * 
+   * | Name | Description |
+   * | ---- | ----------- |
+   * | REGO_NODE_BINDING | A binding. Will have two children, a REGO_NODE_VAR and a REGO_NODE_TERM |
+   * | REGO_NODE_VAR | A variable name. | 
+   * | REGO_NODE_TERM | A term. Will have one child of: REGO_NODE_SCALAR, REGO_NODE_ARRAY, REGO_NODE_SET, REGO_NODE_OBJECT |
+   * | REGO_NODE_SCALAR | A scalar value. Will have one child of: REGO_NODE_INT, REGO_NODE_FLOAT, REGO_NODE_STRING, REGO_NODE_TRUE, REGO_NODE_FALSE, REGO_NODE_NULL, REGO_NODE_UNDEFINED |
+   * | REGO_NODE_ARRAY | An array. Will have one or more children of: REGO_NODE_TERM |
+   * | REGO_NODE_SET | A set. Will have one or more children of: REGO_NODE_TERM |
+   * | REGO_NODE_OBJECT | An object. Will have one or more children of: REGO_NODE_OBJECT_ITEM |
+   * | REGO_NODE_OBJECT_ITEM | An object item. Will have two children, a REGO_NODE_TERM (the key) and a REGO_NODE_TERM (the value) |
+   * | REGO_NODE_INT | An integer value. |
+   * | REGO_NODE_FLOAT | A floating point value. |
+   * | REGO_NODE_STRING | A string value. |
+   * | REGO_NODE_TRUE | A true value. |
+   * | REGO_NODE_FALSE | A false value. |
+   * | REGO_NODE_NULL | A null value. |
+   * | REGO_NODE_UNDEFINED | An undefined value. |
+   * | REGO_NODE_ERROR | An error. Will have three children: REGO_NODE_ERROR_MESSAGE, REGO_NODE_ERROR_AST, and REGO_NODE_ERROR_CODE | 
+   * | REGO_NODE_ERROR_MESSAGE | An error message. |
+   * | REGO_NODE_ERROR_AST | An error AST. |
+   * | REGO_NODE_ERROR_CODE | An error code. |
+   * | REGO_NODE_ERROR_SEQ | An error sequence. Will have one or more children of: REGO_NODE_ERROR |
+   * | REGO_NODE_INTERNAL | An internal node. Use regoNodeTypeName to get the full value. |
+   *
+   * @return The node type.
+   */
   regoEnum regoNodeType(regoNode* node);
+
+  // clang-format on
+
+  /**
+   * Returns the name of the node type as a human-readable string.
+   *
+   * This function supports arbitrary nodes (i.e. it will always produce a
+   * value) including internal nodes which appear in error messages.
+   *
+   * @param node The node.
+   * @return The node type name.
+   */
   const char* regoNodeTypeName(regoNode* node);
+
+  /**
+   * Returns the number of bytes needed to store a 0-terminated string
+   * representing the text value of the node.
+   *
+   * The value returned by this function can be used to allocate a buffer to
+   * pass to regoNodeValue.
+   *
+   * @param node The node.
+   * @return The number of bytes needed to store the text value.
+   */
   regoSize regoNodeValueSize(regoNode* node);
+
+  /**
+   * Populate a buffer with the node value.
+   *
+   * The buffer must be large enough to hold the value. The size of the buffer
+   * can be determined by calling regoNodeValueSize.
+   *
+   * @param node The node.
+   * @param buffer The buffer to populate.
+   * @param size The size of the buffer.
+   * @return REGO_OK if successful, REGO_ERROR_BUFFER_TOO_SMALL otherwise.
+   */
   regoEnum regoNodeValue(regoNode* node, char* buffer, regoSize size);
+
+  /**
+   * Returns the number of children of the node.
+   *
+   * @param node The node.
+   * @return The number of children.
+   */
   regoSize regoNodeSize(regoNode* node);
+
+  /**
+   * Returns the child node at the specified index.
+   *
+   * @param node The node.
+   * @param index The index of the child.
+   * @return The child node.
+   */
   regoNode* regoNodeGet(regoNode* node, regoSize index);
+
+  /**
+   * Returns the number of bytes needed to store a 0-terminated string
+   * representing the JSON representation of the node.
+   *
+   * The value returned by this function can be used to allocate a buffer to
+   * pass to regoNodeJSON.
+   *
+   * @param node The node.
+   * @return The number of bytes needed to store the JSON representation.
+   */
   regoSize regoNodeJSONSize(regoNode* node);
+
+  /**
+   * Populate a buffer with the JSON representation of the node.
+   *
+   * The buffer must be large enough to hold the value. The size of the buffer
+   * can be determined by calling regoNodeJSONSize.
+   *
+   * @param node The node.
+   * @param buffer The buffer to populate.
+   * @param size The size of the buffer.
+   * @return REGO_OK if successful, REGO_ERROR_BUFFER_TOO_SMALL otherwise.
+   */
   regoEnum regoNodeJSON(regoNode* node, char* buffer, regoSize size);
 
 #ifdef __cplusplus
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 3baa6f49..ba3b3384 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -3,7 +3,7 @@ configure_file("${CMAKE_CURRENT_SOURCE_DIR}/version.h.in" "${CMAKE_CURRENT_BINAR
 set( SOURCES
 bigint.cc
 interpreter.cc
-lang.cc
+rego.cc
 parse.cc
 args.cc
 unifier.cc
@@ -12,7 +12,7 @@ value_map.cc
 resolver.cc
 variable.cc
 builtins.cc
-helpers.cc
+internal.cc
 rego_c.cc
 encoding.cc
 passes/input_data.cc
diff --git a/src/builtins/aggregates.cc b/src/builtins/aggregates.cc
index dc9960c2..b66d43b1 100644
--- a/src/builtins/aggregates.cc
+++ b/src/builtins/aggregates.cc
@@ -96,7 +96,7 @@ namespace
     return std::accumulate(
       collection->begin(),
       collection->end(),
-      JSONInt ^ "0",
+      Int ^ "0",
       [](const Node& a, const Node& b) {
         return Resolver::arithinfix(Add ^ "+", a, b);
       });
@@ -114,7 +114,7 @@ namespace
     Node sum = std::accumulate(
       collection->begin(),
       collection->end(),
-      JSONInt ^ "1",
+      Int ^ "1",
       [](const Node& a, const Node& b) {
         return Resolver::arithinfix(Multiply ^ "*", a, b);
       });
@@ -133,17 +133,17 @@ namespace
 
     for (const Node& item : *collection)
     {
-      auto maybe_boolean = unwrap(item, {JSONTrue, JSONFalse});
+      auto maybe_boolean = unwrap(item, {True, False});
       if (maybe_boolean.success)
       {
-        if (maybe_boolean.node->type() == JSONTrue)
+        if (maybe_boolean.node->type() == True)
         {
-          return JSONTrue ^ "true";
+          return True ^ "true";
         }
       }
     }
 
-    return JSONFalse ^ "false";
+    return False ^ "false";
   }
 
   Node all(const Nodes& args)
@@ -157,21 +157,21 @@ namespace
 
     for (const Node& item : *collection)
     {
-      auto maybe_boolean = unwrap(item, {JSONTrue, JSONFalse});
+      auto maybe_boolean = unwrap(item, {True, False});
       if (maybe_boolean.success)
       {
-        if (maybe_boolean.node->type() == JSONFalse)
+        if (maybe_boolean.node->type() == False)
         {
-          return JSONFalse ^ "false";
+          return False ^ "false";
         }
       }
       else
       {
-        return JSONFalse ^ "false";
+        return False ^ "false";
       }
     }
 
-    return JSONTrue ^ "true";
+    return True ^ "true";
   }
 
 }
diff --git a/src/builtins/arrays.cc b/src/builtins/arrays.cc
index 5e70c880..8e9fa99d 100644
--- a/src/builtins/arrays.cc
+++ b/src/builtins/arrays.cc
@@ -51,9 +51,9 @@ namespace
   {
     Node arr = unwrap_arg(args, UnwrapOpt(0).func("array.slice").type(Array));
     Node start_number =
-      unwrap_arg(args, UnwrapOpt(1).func("array.slice").type(JSONInt));
+      unwrap_arg(args, UnwrapOpt(1).func("array.slice").type(Int));
     Node end_number =
-      unwrap_arg(args, UnwrapOpt(2).func("array.slice").type(JSONInt));
+      unwrap_arg(args, UnwrapOpt(2).func("array.slice").type(Int));
 
     std::int64_t raw_start = BigInt(start_number->location()).to_int();
     std::int64_t raw_end = BigInt(end_number->location()).to_int();
diff --git a/src/builtins/bits.cc b/src/builtins/bits.cc
index a12bf9b2..adcd9142 100644
--- a/src/builtins/bits.cc
+++ b/src/builtins/bits.cc
@@ -7,16 +7,14 @@ namespace
   Node and_(const Nodes& args)
   {
     Node x = unwrap_arg(
-      args,
-      UnwrapOpt(0).types({JSONInt}).func("bits.and").specify_number(true));
+      args, UnwrapOpt(0).types({Int}).func("bits.and").specify_number(true));
     if (x->type() == Error)
     {
       return x;
     }
 
     Node y = unwrap_arg(
-      args,
-      UnwrapOpt(1).types({JSONInt}).func("bits.and").specify_number(true));
+      args, UnwrapOpt(1).types({Int}).func("bits.and").specify_number(true));
     if (y->type() == Error)
     {
       return y;
@@ -31,16 +29,14 @@ namespace
   Node lsh(const Nodes& args)
   {
     Node x = unwrap_arg(
-      args,
-      UnwrapOpt(0).types({JSONInt}).func("bits.lsh").specify_number(true));
+      args, UnwrapOpt(0).types({Int}).func("bits.lsh").specify_number(true));
     if (x->type() == Error)
     {
       return x;
     }
 
     Node s = unwrap_arg(
-      args,
-      UnwrapOpt(1).types({JSONInt}).func("bits.lsh").specify_number(true));
+      args, UnwrapOpt(1).types({Int}).func("bits.lsh").specify_number(true));
     if (s->type() == Error)
     {
       return s;
@@ -66,8 +62,7 @@ namespace
   Node negate(const Nodes& args)
   {
     Node x = unwrap_arg(
-      args,
-      UnwrapOpt(0).types({JSONInt}).func("bits.negate").specify_number(true));
+      args, UnwrapOpt(0).types({Int}).func("bits.negate").specify_number(true));
     if (x->type() == Error)
     {
       return x;
@@ -81,14 +76,14 @@ namespace
   Node or_(const Nodes& args)
   {
     Node x = unwrap_arg(
-      args, UnwrapOpt(0).types({JSONInt}).func("bits.or").specify_number(true));
+      args, UnwrapOpt(0).types({Int}).func("bits.or").specify_number(true));
     if (x->type() == Error)
     {
       return x;
     }
 
     Node y = unwrap_arg(
-      args, UnwrapOpt(1).types({JSONInt}).func("bits.or").specify_number(true));
+      args, UnwrapOpt(1).types({Int}).func("bits.or").specify_number(true));
     if (y->type() == Error)
     {
       return y;
@@ -103,16 +98,14 @@ namespace
   Node rsh(const Nodes& args)
   {
     Node x = unwrap_arg(
-      args,
-      UnwrapOpt(0).types({JSONInt}).func("bits.rsh").specify_number(true));
+      args, UnwrapOpt(0).types({Int}).func("bits.rsh").specify_number(true));
     if (x->type() == Error)
     {
       return x;
     }
 
     Node s = unwrap_arg(
-      args,
-      UnwrapOpt(1).types({JSONInt}).func("bits.rsh").specify_number(true));
+      args, UnwrapOpt(1).types({Int}).func("bits.rsh").specify_number(true));
     if (s->type() == Error)
     {
       return s;
@@ -136,16 +129,14 @@ namespace
   Node xor_(const Nodes& args)
   {
     Node x = unwrap_arg(
-      args,
-      UnwrapOpt(0).types({JSONInt}).func("bits.xor").specify_number(true));
+      args, UnwrapOpt(0).types({Int}).func("bits.xor").specify_number(true));
     if (x->type() == Error)
     {
       return x;
     }
 
     Node y = unwrap_arg(
-      args,
-      UnwrapOpt(1).types({JSONInt}).func("bits.xor").specify_number(true));
+      args, UnwrapOpt(1).types({Int}).func("bits.xor").specify_number(true));
     if (x->type() == Error)
     {}
 
diff --git a/src/builtins/casts.cc b/src/builtins/casts.cc
index 39799c63..55a8f0db 100644
--- a/src/builtins/casts.cc
+++ b/src/builtins/casts.cc
@@ -41,7 +41,7 @@ namespace
 
   Node cast_boolean(const Nodes& args)
   {
-    Node boolean = unwrap_arg(args, UnwrapOpt(0).types({JSONTrue, JSONFalse}));
+    Node boolean = unwrap_arg(args, UnwrapOpt(0).types({True, False}));
     if (boolean->type() == Error)
     {
       return boolean;
@@ -63,7 +63,7 @@ namespace
 
   Node cast_null(const Nodes& args)
   {
-    Node null = unwrap_arg(args, UnwrapOpt(0).type(JSONNull));
+    Node null = unwrap_arg(args, UnwrapOpt(0).type(Null));
     if (null->type() == Error)
     {
       return null;
@@ -75,9 +75,7 @@ namespace
   Node to_number(const Nodes& args)
   {
     Node number = unwrap_arg(
-      args,
-      UnwrapOpt(0).types(
-        {JSONInt, JSONFloat, JSONString, JSONTrue, JSONFalse, JSONNull}));
+      args, UnwrapOpt(0).types({Int, Float, JSONString, True, False, Null}));
     if (number->type() == Error)
     {
       return number;
@@ -87,7 +85,7 @@ namespace
     {
       if (BigInt::is_int(number->location()))
       {
-        return JSONInt ^ number->location();
+        return Int ^ number->location();
       }
 
       std::string number_str = get_string(number);
@@ -102,19 +100,19 @@ namespace
       }
     }
 
-    if (number->type() == JSONNull)
+    if (number->type() == Null)
     {
-      return JSONInt ^ "0";
+      return Int ^ "0";
     }
 
-    if (number->type() == JSONTrue)
+    if (number->type() == True)
     {
-      return JSONInt ^ "1";
+      return Int ^ "1";
     }
 
-    if (number->type() == JSONFalse)
+    if (number->type() == False)
     {
-      return JSONInt ^ "0";
+      return Int ^ "0";
     }
 
     return number->clone();
diff --git a/src/builtins/numbers.cc b/src/builtins/numbers.cc
index 46300e82..e68c5745 100644
--- a/src/builtins/numbers.cc
+++ b/src/builtins/numbers.cc
@@ -9,20 +9,20 @@ namespace
   Node abs(const Nodes& args)
   {
     Node number = unwrap_arg(
-      args, UnwrapOpt(0).types({JSONInt, JSONFloat}).message("Not a number"));
+      args, UnwrapOpt(0).types({Int, Float}).message("Not a number"));
     if (number->type() == Error)
     {
       return number;
     }
 
-    if (number->type() == JSONInt)
+    if (number->type() == Int)
     {
       BigInt value = get_int(number);
       if (value.is_negative())
       {
         value = value.negate();
       }
-      return JSONInt ^ value.loc();
+      return Int ^ value.loc();
     }
     else
     {
@@ -31,83 +31,81 @@ namespace
       {
         value *= -1;
       }
-      return JSONFloat ^ std::to_string(value);
+      return Float ^ std::to_string(value);
     }
   }
 
   Node ceil(const Nodes& args)
   {
     Node number = unwrap_arg(
-      args, UnwrapOpt(0).types({JSONInt, JSONFloat}).message("Not a number"));
+      args, UnwrapOpt(0).types({Int, Float}).message("Not a number"));
     if (number->type() == Error)
     {
       return number;
     }
 
-    if (number->type() == JSONInt)
+    if (number->type() == Int)
     {
       return number;
     }
     else
     {
       BigInt value(static_cast<std::int64_t>(std::ceil(get_double(number))));
-      return JSONInt ^ value.loc();
+      return Int ^ value.loc();
     }
   }
 
   Node floor(const Nodes& args)
   {
     Node number = unwrap_arg(
-      args, UnwrapOpt(0).types({JSONInt, JSONFloat}).message("Not a number"));
+      args, UnwrapOpt(0).types({Int, Float}).message("Not a number"));
     if (number->type() == Error)
     {
       return number;
     }
 
-    if (number->type() == JSONInt)
+    if (number->type() == Int)
     {
       return number;
     }
     else
     {
       BigInt value(static_cast<std::int64_t>(std::floor(get_double(number))));
-      return JSONInt ^ value.loc();
+      return Int ^ value.loc();
     }
   }
 
   Node round(const Nodes& args)
   {
     Node number = unwrap_arg(
-      args, UnwrapOpt(0).types({JSONInt, JSONFloat}).message("Not a number"));
+      args, UnwrapOpt(0).types({Int, Float}).message("Not a number"));
     if (number->type() == Error)
     {
       return number;
     }
 
-    if (number->type() == JSONInt)
+    if (number->type() == Int)
     {
       return number;
     }
     else
     {
       BigInt value(static_cast<std::int64_t>(std::round(get_double(number))));
-      return JSONInt ^ value.loc();
+      return Int ^ value.loc();
     }
   }
 
   Node numbers_range(const Nodes& args)
   {
     Node lhs_number = unwrap_arg(
-      args,
-      UnwrapOpt(0).type(JSONInt).func("numbers.range").specify_number(true));
+      args, UnwrapOpt(0).type(Int).func("numbers.range").specify_number(true));
     if (lhs_number->type() == Error)
     {
       return lhs_number;
     }
 
     Node rhs_number = unwrap_arg(
-      args,
-      UnwrapOpt(1).type(JSONInt).func("numbers.range").specify_number(true));
+      args, UnwrapOpt(1).type(Int).func("numbers.range").specify_number(true));
     if (rhs_number->type() == Error)
     {
       return rhs_number;
@@ -121,20 +119,20 @@ namespace
       BigInt curr = lhs;
       while (curr < rhs)
       {
-        array->push_back(Term << (Scalar << (JSONInt ^ curr.loc())));
+        array->push_back(Term << (Scalar << (Int ^ curr.loc())));
         curr = curr.increment();
       }
-      array->push_back(Term << (Scalar << (JSONInt ^ curr.loc())));
+      array->push_back(Term << (Scalar << (Int ^ curr.loc())));
     }
     else
     {
       BigInt curr = lhs;
       while (curr > rhs)
       {
-        array->push_back(Term << (Scalar << (JSONInt ^ curr.loc())));
+        array->push_back(Term << (Scalar << (Int ^ curr.loc())));
         curr = curr.decrement();
       }
-      array->push_back(Term << (Scalar << (JSONInt ^ curr.loc())));
+      array->push_back(Term << (Scalar << (Int ^ curr.loc())));
     }
 
     return array;
@@ -149,8 +147,7 @@ namespace
       return seed_string_node;
     }
 
-    Node n_node =
-      unwrap_arg(args, UnwrapOpt(1).type(JSONInt).func("rand.intn"));
+    Node n_node = unwrap_arg(args, UnwrapOpt(1).type(Int).func("rand.intn"));
     if (n_node->type() == Error)
     {
       return n_node;
@@ -162,7 +159,7 @@ namespace
     auto seed = static_cast<std::mt19937::result_type>(hash(seed_string));
     std::mt19937 rng(seed);
     std::size_t value = rng() % n;
-    return JSONInt ^ std::to_string(value);
+    return Int ^ std::to_string(value);
   }
 }
 
diff --git a/src/builtins/objects.cc b/src/builtins/objects.cc
index 4ad8af28..5735dc62 100644
--- a/src/builtins/objects.cc
+++ b/src/builtins/objects.cc
@@ -94,7 +94,7 @@ namespace
     }
     else if (collection->type() == Array)
     {
-      auto maybe_key = unwrap(keys->at(index), {JSONInt});
+      auto maybe_key = unwrap(keys->at(index), {Int});
       if (!maybe_key.success)
       {
         return std::nullopt;
@@ -367,10 +367,10 @@ namespace
 
     if (is_subset(super, sub))
     {
-      return JSONTrue ^ "true";
+      return True ^ "true";
     }
 
-    return JSONFalse ^ "false";
+    return False ^ "false";
   }
 
   Node object_union(const Node& lhs, const Node& rhs)
diff --git a/src/builtins/regex.cc b/src/builtins/regex.cc
index 4858992e..0fabfa98 100644
--- a/src/builtins/regex.cc
+++ b/src/builtins/regex.cc
@@ -284,7 +284,7 @@ namespace
     }
 
     Node number_node =
-      unwrap_arg(args, UnwrapOpt(2).type({JSONInt}).func("regex.find_n"));
+      unwrap_arg(args, UnwrapOpt(2).type({Int}).func("regex.find_n"));
     if (number_node->type() == Error)
     {
       return number_node;
@@ -338,7 +338,7 @@ namespace
     }
 
     Node number_node =
-      unwrap_arg(args, UnwrapOpt(2).type({JSONInt}).func("regex.find_n"));
+      unwrap_arg(args, UnwrapOpt(2).type({Int}).func("regex.find_n"));
     if (number_node->type() == Error)
     {
       return number_node;
diff --git a/src/builtins/semver.cc b/src/builtins/semver.cc
index 2510f401..4b08bf66 100644
--- a/src/builtins/semver.cc
+++ b/src/builtins/semver.cc
@@ -160,13 +160,13 @@ namespace
 
     if (*a_semver < *b_semver)
     {
-      return JSONInt ^ "-1";
+      return Int ^ "-1";
     }
     if (*b_semver < *a_semver)
     {
-      return JSONInt ^ "1";
+      return Int ^ "1";
     }
-    return JSONInt ^ "0";
+    return Int ^ "0";
   }
 
   Node is_valid(const Nodes& args)
@@ -174,17 +174,17 @@ namespace
     auto vsn = unwrap(args[0], {JSONString});
     if (!vsn.success)
     {
-      return JSONFalse ^ "false";
+      return False ^ "false";
     }
 
     std::string vsn_str = get_string(vsn.node);
     auto semver = parse_semver(vsn_str);
     if (semver.has_value())
     {
-      return JSONTrue ^ "true";
+      return True ^ "true";
     }
 
-    return JSONFalse ^ "false";
+    return False ^ "false";
   }
 }
 
diff --git a/src/builtins/strings.cc b/src/builtins/strings.cc
index 07165261..50374aa4 100644
--- a/src/builtins/strings.cc
+++ b/src/builtins/strings.cc
@@ -127,21 +127,21 @@ namespace
 
   Node format_int(const Nodes& args)
   {
-    Node number = unwrap_arg(
-      args, UnwrapOpt(0).types({JSONInt, JSONFloat}).func("format_int"));
+    Node number =
+      unwrap_arg(args, UnwrapOpt(0).types({Int, Float}).func("format_int"));
     if (number->type() == Error)
     {
       return number;
     }
 
-    Node base = unwrap_arg(args, UnwrapOpt(1).type(JSONInt).func("format_int"));
+    Node base = unwrap_arg(args, UnwrapOpt(1).type(Int).func("format_int"));
     if (base->type() == Error)
     {
       return base;
     }
 
     std::int64_t value;
-    if (number->type() == JSONFloat)
+    if (number->type() == Float)
     {
       value = static_cast<std::int64_t>(std::floor(get_double(number)));
     }
@@ -195,10 +195,10 @@ namespace
     auto pos = haystack_runes.find(needle_runes);
     if (pos == haystack_runes.npos)
     {
-      return JSONInt ^ "-1";
+      return Int ^ "-1";
     }
 
-    return JSONInt ^ std::to_string(pos);
+    return Int ^ std::to_string(pos);
   }
 
   Node indexof_n(const Nodes& args)
@@ -223,7 +223,7 @@ namespace
     auto pos = haystack_runes.find(needle_runes);
     while (pos != haystack_runes.npos)
     {
-      array->push_back(JSONInt ^ std::to_string(pos));
+      array->push_back(Int ^ std::to_string(pos));
       pos = haystack_runes.find(needle_runes, pos + 1);
     }
 
@@ -483,7 +483,7 @@ namespace
           break;
 
         case PrintVerbType::Integer:
-          node = unwrap_arg({node}, UnwrapOpt(0).type(JSONInt).func("sprintf"));
+          node = unwrap_arg({node}, UnwrapOpt(0).type(Int).func("sprintf"));
           if (node->type() == Error)
           {
             return node;
@@ -495,7 +495,7 @@ namespace
 
         case PrintVerbType::Double:
           node = unwrap_arg(
-            {node}, UnwrapOpt(0).types({JSONInt, JSONFloat}).func("sprintf"));
+            {node}, UnwrapOpt(0).types({Int, Float}).func("sprintf"));
           if (node->type() == Error)
           {
             return node;
@@ -579,12 +579,12 @@ namespace
       {
         if (search_str.starts_with(base_str))
         {
-          return JSONTrue ^ "true";
+          return True ^ "true";
         }
       }
     }
 
-    return JSONFalse ^ "false";
+    return False ^ "false";
   }
 
   Node any_suffix_match(const Nodes& args)
@@ -649,12 +649,12 @@ namespace
       {
         if (search_str.ends_with(base_str))
         {
-          return JSONTrue ^ "true";
+          return True ^ "true";
         }
       }
     }
 
-    return JSONFalse ^ "false";
+    return False ^ "false";
   }
 
   Node replace_n(const Nodes& args)
@@ -733,14 +733,12 @@ namespace
     {
       return value;
     }
-    Node offset =
-      unwrap_arg(args, UnwrapOpt(1).type(JSONInt).func("substring"));
+    Node offset = unwrap_arg(args, UnwrapOpt(1).type(Int).func("substring"));
     if (offset->type() == Error)
     {
       return offset;
     }
-    Node length =
-      unwrap_arg(args, UnwrapOpt(2).type(JSONInt).func("substring"));
+    Node length = unwrap_arg(args, UnwrapOpt(2).type(Int).func("substring"));
     if (length->type() == Error)
     {
       return length;
diff --git a/src/builtins/time.cc b/src/builtins/time.cc
index 0aa49b9f..2252e9d1 100644
--- a/src/builtins/time.cc
+++ b/src/builtins/time.cc
@@ -12,7 +12,7 @@ namespace
     auto now = high_resolution_clock::now().time_since_epoch();
     auto now_ns = duration_cast<nanoseconds>(now).count();
 
-    return JSONInt ^ std::to_string(now_ns);
+    return Int ^ std::to_string(now_ns);
   }
 }
 
diff --git a/src/builtins/types.cc b/src/builtins/types.cc
index 70112f4e..1ee775f4 100644
--- a/src/builtins/types.cc
+++ b/src/builtins/types.cc
@@ -11,17 +11,17 @@ namespace
 
   Node is_boolean(const Nodes& args)
   {
-    return Resolver::scalar(is_instance(args[0], {JSONTrue, JSONFalse}));
+    return Resolver::scalar(is_instance(args[0], {True, False}));
   }
 
   Node is_null(const Nodes& args)
   {
-    return Resolver::scalar(is_instance(args[0], {JSONNull}));
+    return Resolver::scalar(is_instance(args[0], {Null}));
   }
 
   Node is_number(const Nodes& args)
   {
-    return Resolver::scalar(is_instance(args[0], {JSONInt, JSONFloat}));
+    return Resolver::scalar(is_instance(args[0], {Int, Float}));
   }
 
   Node is_object(const Nodes& args)
diff --git a/src/builtins/units.cc b/src/builtins/units.cc
index 4d7fa7cf..d3448d5d 100644
--- a/src/builtins/units.cc
+++ b/src/builtins/units.cc
@@ -92,12 +92,12 @@ namespace
 
     if (num_decimals == 0)
     {
-      return JSONInt ^ num_str;
+      return Int ^ num_str;
     }
 
     if (num_decimals == 1)
     {
-      return JSONFloat ^ num_str;
+      return Float ^ num_str;
     }
 
     return err(x, errors.parse, EvalBuiltInError);
@@ -105,20 +105,20 @@ namespace
 
   Node scale(const Node& num, const BigInt& scale, bool round)
   {
-    if (num->type() == JSONInt)
+    if (num->type() == Int)
     {
       BigInt num_int(num->location());
-      return JSONInt ^ (num_int * scale).loc();
+      return Int ^ (num_int * scale).loc();
     }
 
-    if (num->type() == JSONFloat)
+    if (num->type() == Float)
     {
       double result = get_double(num) * scale.to_int();
       if (round)
       {
         result = std::round(result);
         Node result_node = Resolver::scalar(result);
-        return JSONInt ^ result_node->location();
+        return Int ^ result_node->location();
       }
 
       return Resolver::scalar(result);
@@ -129,7 +129,7 @@ namespace
 
   Node scale(const Node& num, double scale)
   {
-    if (num->type() == JSONFloat || num->type() == JSONInt)
+    if (num->type() == Float || num->type() == Int)
     {
       return Resolver::scalar(get_double(num) * scale);
     }
diff --git a/src/encoding.cc b/src/encoding.cc
index 5ca212dc..ba317b6e 100644
--- a/src/encoding.cc
+++ b/src/encoding.cc
@@ -2,14 +2,14 @@
 
 namespace rego
 {
-  std::string to_json(const Node& node, bool sort, bool rego_set)
+  std::string to_json(const Node& node, bool sort, bool set_as_array)
   {
     std::ostringstream buf;
-    if (node->type() == JSONInt)
+    if (node->type() == Int)
     {
       buf << node->location().view();
     }
-    else if (node->type() == JSONFloat)
+    else if (node->type() == Float)
     {
       try
       {
@@ -34,15 +34,15 @@ namespace rego
         buf << str;
       }
     }
-    else if (node->type() == JSONTrue)
+    else if (node->type() == True)
     {
       buf << "true";
     }
-    else if (node->type() == JSONFalse)
+    else if (node->type() == False)
     {
       buf << "false";
     }
-    else if (node->type() == JSONNull)
+    else if (node->type() == Null)
     {
       buf << "null";
     }
@@ -59,7 +59,7 @@ namespace rego
       std::vector<std::string> items;
       for (const auto& child : *node)
       {
-        items.push_back(to_json(child, sort, rego_set));
+        items.push_back(to_json(child, sort, set_as_array));
       }
 
       if (sort)
@@ -80,7 +80,7 @@ namespace rego
       std::vector<std::string> items;
       for (const auto& child : *node)
       {
-        items.push_back(to_json(child, sort, rego_set));
+        items.push_back(to_json(child, sort, set_as_array));
       }
 
       if (sort)
@@ -88,13 +88,13 @@ namespace rego
         std::sort(items.begin(), items.end());
       }
 
-      if (rego_set)
+      if (set_as_array)
       {
-        buf << "<";
+        buf << "[";
       }
       else
       {
-        buf << "[";
+        buf << "<";
       }
       std::string sep = "";
       for (const auto& item : items)
@@ -103,13 +103,13 @@ namespace rego
         sep = ", ";
       }
 
-      if (rego_set)
+      if (set_as_array)
       {
-        buf << ">";
+        buf << "]";
       }
       else
       {
-        buf << "]";
+        buf << ">";
       }
     }
     else if (node->type() == Object || node->type() == DataObject)
@@ -119,12 +119,12 @@ namespace rego
       {
         auto key = child / Key;
         auto value = child / Val;
-        std::string key_str = to_json(key, sort, rego_set);
+        std::string key_str = to_json(key, sort, set_as_array);
         if (!key_str.starts_with('"') || !key_str.ends_with('"'))
         {
           key_str = '"' + key_str + '"';
         }
-        items[key_str] = to_json(value, sort, rego_set);
+        items[key_str] = to_json(value, sort, set_as_array);
       }
 
       buf << "{";
@@ -141,12 +141,12 @@ namespace rego
       node->type() == Scalar || node->type() == Term ||
       node->type() == DataTerm)
     {
-      return to_json(node->front(), sort, rego_set);
+      return to_json(node->front(), sort, set_as_array);
     }
     else if (node->type() == Binding)
     {
       buf << (node / Var)->location().view() << " = "
-          << to_json(node / Term, sort, rego_set);
+          << to_json(node / Term, sort, set_as_array);
     }
     else if (node->type() == TermSet)
     {
@@ -154,7 +154,7 @@ namespace rego
       std::string sep = "";
       for (const auto& child : *node)
       {
-        buf << sep << to_json(child, sort, rego_set);
+        buf << sep << to_json(child, sort, set_as_array);
         sep = ", ";
       }
       buf << "}";
diff --git a/src/helpers.cc b/src/internal.cc
similarity index 91%
rename from src/helpers.cc
rename to src/internal.cc
index 2f3dfa4c..140c74b4 100644
--- a/src/helpers.cc
+++ b/src/internal.cc
@@ -1,5 +1,4 @@
 #include "internal.hh"
-#include "version.h"
 
 #ifdef _WIN32
 #include <codecvt>
@@ -375,13 +374,13 @@ namespace rego
 
   BigInt get_int(const Node& node)
   {
-    assert(node->type() == JSONInt);
+    assert(node->type() == Int);
     return ::get_int(node);
   }
 
   double get_double(const Node& node)
   {
-    assert(node->type() == JSONFloat || node->type() == JSONInt);
+    assert(node->type() == Float || node->type() == Int);
     return ::get_double(node);
   }
 
@@ -408,8 +407,8 @@ namespace rego
 
   bool get_bool(const Node& node)
   {
-    assert(node->type() == JSONTrue || node->type() == JSONFalse);
-    return node->type() == JSONTrue;
+    assert(node->type() == True || node->type() == False);
+    return node->type() == True;
   }
 
   bool is_truthy(const Node& node)
@@ -424,7 +423,7 @@ namespace rego
     if (value->type() == Scalar)
     {
       value = value->front();
-      return value->type() != JSONFalse;
+      return value->type() != False;
     }
 
     if (
@@ -472,7 +471,7 @@ namespace rego
       value = value->front();
     }
 
-    if (value->type() == JSONFalse)
+    if (value->type() == False)
     {
       return true;
     }
@@ -487,7 +486,7 @@ namespace rego
 
   std::string type_name(const Token& type, bool specify_number)
   {
-    if (type == JSONInt)
+    if (type == Int)
     {
       if (specify_number)
       {
@@ -496,7 +495,7 @@ namespace rego
       return "number";
     }
 
-    if (type == JSONFloat)
+    if (type == Float)
     {
       if (specify_number)
       {
@@ -510,7 +509,7 @@ namespace rego
       return "string";
     }
 
-    if (type == JSONTrue || type == JSONFalse)
+    if (type == True || type == False)
     {
       return "boolean";
     }
@@ -729,4 +728,55 @@ namespace rego
       return false;
     }
   }
+
+  Node scalar(BigInt value)
+  {
+    return Resolver::scalar(value);
+  }
+
+  Node scalar(double value)
+  {
+    return Resolver::scalar(value);
+  }
+
+  Node scalar(bool value)
+  {
+    return Resolver::scalar(value);
+  }
+
+  Node scalar(const char* value)
+  {
+    return Resolver::scalar(value);
+  }
+
+  Node scalar(const std::string& value)
+  {
+    return Resolver::scalar(value);
+  }
+
+  Node scalar()
+  {
+    return Resolver::scalar();
+  }
+
+  Node object_item(const Node& key_term, const Node& val_term)
+  {
+    return ObjectItem << Resolver::to_term(key_term)
+                      << Resolver::to_term(val_term);
+  }
+
+  Node object(const Nodes& object_items)
+  {
+    return Object << object_items;
+  }
+
+  Node array(const Nodes& array_members)
+  {
+    return Array << array_members;
+  }
+
+  Node set(const Nodes& set_members)
+  {
+    return Set << set_members;
+  }
 }
\ No newline at end of file
diff --git a/src/internal.hh b/src/internal.hh
index cefb5ddd..f0598455 100644
--- a/src/internal.hh
+++ b/src/internal.hh
@@ -5,20 +5,32 @@
 
 #include "rego/rego.hh"
 
-#define LOG(...) Logger::print(Logger::indent, __VA_ARGS__)
+#define LOG_ERROR(...) \
+  Logger::print(LogLevel::Error, Logger::indent, "Error: ", __VA_ARGS__)
+#define LOG_WARNING(...) \
+  Logger::print(LogLevel::Warning, Logger::indent, "Warning: ", __VA_ARGS__)
+#define LOG_INFO(...) Logger::print(LogLevel::Info, Logger::indent, __VA_ARGS__)
+#define LOG_DEBUG(...) \
+  Logger::print(LogLevel::Debug, Logger::indent, __VA_ARGS__)
+#define LOG_Trace(...) \
+  Logger::print(LogLevel::Trace, Logger::indent, __VA_ARGS__)
+#define LOG(...) Logger::print(LogLevel::Debug, Logger::indent, __VA_ARGS__)
 #define LOG_HEADER(message, header) \
-  Logger::print(Logger::indent, (header), (message), (header))
-#define LOG_VECTOR(vector) Logger::print_vector_inline((vector))
+  Logger::print(LogLevel::Debug, Logger::indent, (header), (message), (header))
+#define LOG_VECTOR(vector) \
+  Logger::print_vector_inline(LogLevel::Debug, (vector))
 #define LOG_VECTOR_CUSTOM(vector, transform) \
-  Logger::print_vector_custom((vector), (transform))
-#define LOG_MAP_VALUES(map) Logger::print_map_values((map))
+  Logger::print_vector_custom(LogLevel::Debug, (vector), (transform))
+#define LOG_MAP_VALUES(map) Logger::print_map_values(LogLevel::Debug, (map))
 #define LOG_INDENT() Logger::increase_print_indent()
 #define LOG_UNINDENT() Logger::decrease_print_indent()
 
 namespace rego
 {
+  std::vector<PassCheck> passes(const BuiltIns& builtins);
+
   const inline auto ScalarToken =
-    T(JSONInt) / T(JSONFloat) / T(JSONTrue) / T(JSONFalse) / T(JSONNull);
+    T(Int) / T(Float) / T(True) / T(False) / T(Null);
   const inline auto ArithToken =
     T(Add) / T(Subtract) / T(Multiply) / T(Divide) / T(Modulo);
   const inline auto ArithInfixArg = T(Expr) / T(NumTerm) / T(Ref) /
@@ -45,45 +57,6 @@ namespace rego
   inline const std::set<Token> RuleTypes(
     {RuleComp, RuleFunc, RuleSet, RuleObj, DefaultRule});
 
-  struct UnwrapResult
-  {
-    Node node;
-    bool success;
-  };
-
-  class UnwrapOpt
-  {
-  public:
-    UnwrapOpt(std::size_t index);
-    bool exclude_got() const;
-    UnwrapOpt& exclude_got(bool exclude_got);
-    bool specify_number() const;
-    UnwrapOpt& specify_number(bool specify_number);
-    const std::string& code() const;
-    UnwrapOpt& code(const std::string& value);
-    const std::string& pre() const;
-    UnwrapOpt& pre(const std::string& value);
-    const std::string& message() const;
-    UnwrapOpt& message(const std::string& value);
-    const std::string& func() const;
-    UnwrapOpt& func(const std::string& value);
-    const std::vector<Token>& types() const;
-    UnwrapOpt& types(const std::vector<Token>& value);
-    UnwrapOpt& type(const Token& value);
-
-    Node unwrap(const Nodes& args) const;
-
-  private:
-    bool m_exclude_got;
-    bool m_specify_number;
-    std::string m_code;
-    std::string m_prefix;
-    std::string m_message;
-    std::string m_func;
-    std::vector<Token> m_types;
-    std::size_t m_index;
-  };
-
   bool all_alnum(const std::string_view& str);
   bool contains_local(const Node& node);
   bool contains_ref(const Node& node);
@@ -98,14 +71,8 @@ namespace rego
   bool is_undefined(const Node& node);
   bool is_ref_to_type(const Node& var, const std::set<Token>& types);
   std::string strip_quotes(const std::string_view& str);
-  BigInt get_int(const Node& node);
-  double get_double(const Node& node);
-  std::string get_string(const Node& node);
-  bool get_bool(const Node& node);
   std::string type_name(const Token& type, bool specify_number = false);
   std::string type_name(const Node& node, bool specify_number = false);
-  Node unwrap_arg(const Nodes& args, const UnwrapOpt& options);
-  UnwrapResult unwrap(const Node& term, const std::set<Token>& types);
 
   using namespace trieste;
   using PrintNode = std::ostream& (*)(std::ostream&, const Node&);
@@ -230,7 +197,7 @@ namespace rego
 
   struct Logger
   {
-    static bool enabled;
+    static LogLevel maximum_level;
     static std::string indent;
 
     static inline void increase_print_indent()
@@ -244,28 +211,29 @@ namespace rego
     }
 
     template <typename T>
-    static inline void print(const T& value)
+    static inline void print(LogLevel level, const T& value)
     {
-      if (enabled)
+      if (level <= maximum_level)
       {
         std::cout << value << std::endl;
       }
     }
 
     template <typename T, typename... Types>
-    static void print(T head, Types... tail)
+    static void print(LogLevel level, T head, Types... tail)
     {
-      if (enabled)
+      if (level <= maximum_level)
       {
         std::cout << head;
-        print(tail...);
+        print(level, tail...);
       }
     }
 
     template <typename T>
-    static inline void print_vector_inline(const std::vector<T>& values)
+    static inline void print_vector_inline(
+      LogLevel level, const std::vector<T>& values)
     {
-      if (enabled)
+      if (level <= maximum_level)
       {
         std::cout << indent << "[";
         std::string sep = "";
@@ -280,28 +248,29 @@ namespace rego
 
     template <typename T, typename P>
     static inline void print_vector_custom(
-      const std::vector<T>& values, P (*transform)(const T&))
+      LogLevel level, const std::vector<T>& values, P (*transform)(const T&))
     {
-      if (enabled)
+      if (level <= maximum_level)
       {
         for (auto& value : values)
         {
-          print(indent, transform(value));
+          print(level, indent, transform(value));
         }
       }
     }
 
     template <typename K, typename V>
-    static inline void print_map_values(const std::map<K, V>& values)
+    static inline void print_map_values(
+      LogLevel level, const std::map<K, V>& values)
     {
-      if (enabled)
+      if (level <= maximum_level)
       {
-        print(indent, "{");
+        print(level, indent, "{");
         for (auto& [_, value] : values)
         {
-          print(indent, "  ", value);
+          print(level, indent, "  ", value);
         }
-        print(indent, "}");
+        print(level, indent, "}");
       }
     }
   };
diff --git a/src/interpreter.cc b/src/interpreter.cc
index 4ac83570..0e95a8e8 100644
--- a/src/interpreter.cc
+++ b/src/interpreter.cc
@@ -2,6 +2,10 @@
 
 namespace rego
 {
+  using clock = std::chrono::high_resolution_clock;
+  using duration = std::chrono::high_resolution_clock::duration;
+  using timestamp = std::chrono::high_resolution_clock::time_point;
+
   Interpreter::Interpreter() :
     m_parser(parser()),
     m_wf_parser(wf_parser),
@@ -44,7 +48,7 @@ namespace rego
       throw std::runtime_error("Module file does not exist");
     }
 
-    LOG("Adding module file: ", path);
+    LOG_INFO("Adding module file: ", path);
     auto file_ast = m_parser.sub_parse(path);
     insert_module(file_ast);
   }
@@ -55,7 +59,7 @@ namespace rego
     auto module_source = SourceDef::synthetic(contents);
     auto module = m_parser.sub_parse(name, File, module_source);
     insert_module(module);
-    LOG("Adding module: ", name, "(", contents.size(), " bytes)");
+    LOG_INFO("Adding module: ", name, "(", contents.size(), " bytes)");
   }
 
   void Interpreter::add_data_json_file(const std::filesystem::path& path)
@@ -65,7 +69,7 @@ namespace rego
       throw std::runtime_error("Data file does not exist");
     }
 
-    LOG("Adding data file: ", path);
+    LOG_INFO("Adding data file: ", path);
     auto file_ast = m_parser.sub_parse(path);
     m_data_seq->push_back(file_ast);
   }
@@ -75,13 +79,13 @@ namespace rego
     auto data_source = SourceDef::synthetic(json);
     auto data = m_parser.sub_parse("data", File, data_source);
     m_data_seq->push_back(data);
-    LOG("Adding data (", json.size(), " bytes)");
+    LOG_INFO("Adding data (", json.size(), " bytes)");
   }
 
   void Interpreter::add_data(const Node& node)
   {
     m_data_seq->push_back(node);
-    LOG("Adding data AST");
+    LOG_INFO("Adding data AST");
   }
 
   void Interpreter::set_input_json_file(const std::filesystem::path& path)
@@ -91,14 +95,14 @@ namespace rego
       throw std::runtime_error("Input file does not exist");
     }
 
-    LOG("Setting input from file: ", path);
+    LOG_INFO("Setting input from file: ", path);
     auto file_ast = m_parser.sub_parse(path);
     m_input = Input << file_ast;
   }
 
   void Interpreter::set_input_json(const std::string& json)
   {
-    LOG("Setting input (", json.size(), " bytes)");
+    LOG_INFO("Setting input (", json.size(), " bytes)");
     auto input_source = SourceDef::synthetic(json);
     auto ast = m_parser.sub_parse("input", File, input_source);
     m_input = Input << ast;
@@ -106,7 +110,7 @@ namespace rego
 
   void Interpreter::set_input(const Node& node)
   {
-    LOG("Setting input AST");
+    LOG_INFO("Setting input AST");
     m_input = Input << node;
   }
 
@@ -136,7 +140,7 @@ namespace rego
 
   Node Interpreter::raw_query(const std::string& query_expr) const
   {
-    LOG("Query: ", query_expr);
+    LOG_INFO("Query: ", query_expr);
     auto ast = NodeDef::create(Top);
     auto rego = NodeDef::create(rego::Rego);
     auto query_src = SourceDef::synthetic(query_expr);
@@ -164,9 +168,13 @@ namespace rego
       return get_errors(ast);
     }
 
+    const std::string delim = "\t";
+    LOG_INFO("Name\tPasses\tChanges\tTime(ms)");
     auto passes = rego::passes(m_builtins);
+    timestamp start = clock::now();
     for (std::size_t i = 0; i < passes.size(); ++i)
     {
+      timestamp pass_start = clock::now();
       auto& [pass_name, pass, wf] = passes[i];
       wf::push_back(wf);
       auto [new_ast, count, changes] = pass->run(ast);
@@ -181,6 +189,17 @@ namespace rego
         ok = wf->check(ast, std::cout) && ok;
       }
 
+      duration pass_elapsed = clock::now() - pass_start;
+      LOG_INFO(
+        pass_name,
+        delim,
+        count,
+        delim,
+        changes,
+        delim,
+        std::chrono::duration_cast<std::chrono::milliseconds>(pass_elapsed)
+          .count());
+
       Node errors = get_errors(ast);
       if (errors->size() > 0)
       {
@@ -195,14 +214,24 @@ namespace rego
           error << "Failed at pass " << pass_name << std::endl;
           ast->errors(error);
           errors->push_back(err(ast, error.str(), "well_formed_error"));
-          LOG(error.str());
+          LOG_INFO(error.str());
         }
 
         return errors;
       }
     }
 
-    LOG("Query result: ", ast);
+    duration elapsed = clock::now() - start;
+    LOG_INFO(
+      "Total",
+      delim,
+      "-",
+      delim,
+      "-",
+      delim,
+      std::chrono::duration_cast<std::chrono::milliseconds>(elapsed).count());
+
+    LOG_INFO("Query result: ", ast);
     return ast;
   }
 
@@ -233,7 +262,7 @@ namespace rego
     {
       for (auto result : *ast)
       {
-        output_buf << rego::to_json(result) << std::endl;
+        output_buf << rego::to_json(result, false, true) << std::endl;
       }
     }
 
@@ -312,17 +341,6 @@ namespace rego
     std::cerr << "Could not open " << output << " for writing." << std::endl;
   }
 
-  Interpreter& Interpreter::executable(const std::filesystem::path& path)
-  {
-    m_parser.executable(path);
-    return *this;
-  }
-
-  const std::filesystem::path& Interpreter::executable() const
-  {
-    return m_parser.executable();
-  }
-
   BuiltIns& Interpreter::builtins()
   {
     return m_builtins;
diff --git a/src/parse.cc b/src/parse.cc
index 6d9ad117..4148cef5 100644
--- a/src/parse.cc
+++ b/src/parse.cc
@@ -13,11 +13,13 @@ namespace rego
   {
     // TODO add valid non-alphanum characters
     std::ostringstream buf;
+    buf << '"';
     std::size_t length = rnd() % max_string_length;
     for (std::size_t i = 0; i < length; ++i)
     {
       buf << alphanumeric[rnd() % alphanumeric.size()];
     }
+    buf << '"';
     return buf.str();
   }
 
@@ -26,11 +28,13 @@ namespace rego
   {
     // TODO add valid non-alphanum characters
     std::ostringstream buf;
+    buf << '`';
     std::size_t length = rnd() % max_string_length;
     for (std::size_t i = 0; i < length; ++i)
     {
       buf << alphanumeric[rnd() % alphanumeric.size()];
     }
+    buf << '`';
     return buf.str();
   }
 
@@ -155,7 +159,7 @@ namespace rego
 
         // Float.
         R"([[:digit:]]+\.[[:digit:]]+(?:e[+-]?[[:digit:]]+)?\b)" >>
-          [](auto& m) { m.add(JSONFloat); },
+          [](auto& m) { m.add(Float); },
 
         // String.
         R"("(?:\\(?:["\\\/bfnrtx]|u[a-fA-F0-9]{4})|[^"\\\0-\x1F\x7F]+)*")" >>
@@ -165,20 +169,20 @@ namespace rego
         R"(`[^`]*`)" >> [](auto& m) { m.add(RawString); },
 
         // Int.
-        R"([[:digit:]]+\b)" >> [](auto& m) { m.add(JSONInt); },
+        R"([[:digit:]]+\b)" >> [](auto& m) { m.add(Int); },
 
         // Float with exponent but no decimal.
         R"([[:digit:]]+(?:e[+-]?[[:digit:]]+)?\b)" >>
-          [](auto& m) { m.add(JSONFloat); },
+          [](auto& m) { m.add(Float); },
 
         // True.
-        "true\\b" >> [](auto& m) { m.add(JSONTrue); },
+        "true\\b" >> [](auto& m) { m.add(True); },
 
         // False.
-        "false\\b" >> [](auto& m) { m.add(JSONFalse); },
+        "false\\b" >> [](auto& m) { m.add(False); },
 
         // Null.
-        "null\\b" >> [](auto& m) { m.add(JSONNull); },
+        "null\\b" >> [](auto& m) { m.add(Null); },
 
         // Default.
         "default\\b" >> [](auto& m) { m.add(Default); },
@@ -272,15 +276,15 @@ namespace rego
     p.done([](auto& m) { m.term({List, Some, With}); });
 
     p.gen({
-      JSONInt >> [](auto& rnd) { return std::to_string(rnd() % 100); },
-      JSONFloat >>
+      Int >> [](auto& rnd) { return std::to_string(rnd() % 100); },
+      Float >>
         [](auto& rnd) {
           std::uniform_real_distribution<> dist(-10.0, 10.0);
           return std::to_string(dist(rnd));
         },
-      JSONTrue >> [](auto&) { return "true"; },
-      JSONFalse >> [](auto&) { return "false"; },
-      JSONNull >> [](auto&) { return "null"; },
+      True >> [](auto&) { return "true"; },
+      False >> [](auto&) { return "false"; },
+      Null >> [](auto&) { return "null"; },
       JSONString >> [](auto& rnd) { return rand_string(rnd); },
       RawString >> [](auto& rnd) { return rand_raw_string(rnd); },
     });
diff --git a/src/passes/compr.cc b/src/passes/compr.cc
index 606adf2c..d1541afa 100644
--- a/src/passes/compr.cc
+++ b/src/passes/compr.cc
@@ -90,7 +90,7 @@ namespace rego
             if (body->type() == Empty)
             {
               body = UnifyBody
-                << (Literal << (Expr << (Term << (Scalar << (JSONTrue)))));
+                << (Literal << (Expr << (Term << (Scalar << (True)))));
             }
 
             body = NestedBody << (Key ^ compr) << body;
diff --git a/src/passes/constants.cc b/src/passes/constants.cc
index c702b9fc..f9b467b2 100644
--- a/src/passes/constants.cc
+++ b/src/passes/constants.cc
@@ -120,14 +120,14 @@ namespace rego
                     << (UnifyBody
                         << (LiteralEnum << (Var ^ item) << _(Expr))
                         << (Literal
-                            << (Expr << (RefTerm << _(Val)) << Unify
-                                     << (RefTerm
-                                         << (Ref << (RefHead << (Var ^ item))
-                                                 << (RefArgSeq
-                                                     << (RefArgBrack
-                                                         << (Scalar
-                                                             << (JSONInt ^
-                                                                 "1"))))))))
+                            << (Expr
+                                << (RefTerm << _(Val)) << Unify
+                                << (RefTerm
+                                    << (Ref
+                                        << (RefHead << (Var ^ item))
+                                        << (RefArgSeq
+                                            << (RefArgBrack
+                                                << (Scalar << (Int ^ "1"))))))))
                         << (LiteralNot << _(UnifyBody)))));
         },
 
@@ -148,24 +148,24 @@ namespace rego
                     << (UnifyBody
                         << (LiteralEnum << (Var ^ item) << _(Expr))
                         << (Literal
-                            << (Expr << (RefTerm << _(Idx)->clone()) << Unify
-                                     << (RefTerm
-                                         << (Ref << (RefHead << (Var ^ item))
-                                                 << (RefArgSeq
-                                                     << (RefArgBrack
-                                                         << (Scalar
-                                                             << (JSONInt ^
-                                                                 "0"))))))))
+                            << (Expr
+                                << (RefTerm << _(Idx)->clone()) << Unify
+                                << (RefTerm
+                                    << (Ref
+                                        << (RefHead << (Var ^ item))
+                                        << (RefArgSeq
+                                            << (RefArgBrack
+                                                << (Scalar << (Int ^ "0"))))))))
 
                         << (Literal
-                            << (Expr << (RefTerm << _(Val)->clone()) << Unify
-                                     << (RefTerm
-                                         << (Ref << (RefHead << (Var ^ item))
-                                                 << (RefArgSeq
-                                                     << (RefArgBrack
-                                                         << (Scalar
-                                                             << (JSONInt ^
-                                                                 "1"))))))))
+                            << (Expr
+                                << (RefTerm << _(Val)->clone()) << Unify
+                                << (RefTerm
+                                    << (Ref
+                                        << (RefHead << (Var ^ item))
+                                        << (RefArgSeq
+                                            << (RefArgBrack
+                                                << (Scalar << (Int ^ "1"))))))))
                         << (LiteralNot << _(UnifyBody)))));
         },
 
diff --git a/src/passes/enumerate.cc b/src/passes/enumerate.cc
index 7521a905..b0dec37f 100644
--- a/src/passes/enumerate.cc
+++ b/src/passes/enumerate.cc
@@ -84,7 +84,7 @@ namespace rego
           Node body = UnifyBody << _[Tail];
           if (body->size() == 0)
           {
-            body << (Literal << (Expr << (Term << (Scalar << JSONTrue))));
+            body << (Literal << (Expr << (Term << (Scalar << True))));
           }
           return Seq << (Local << (Var ^ itemseq) << Undefined)
                      << (Literal
@@ -184,7 +184,7 @@ namespace rego
                                     << (SimpleRef
                                         << (Var ^ item)
                                         << (RefArgBrack
-                                            << (Scalar << (JSONInt ^ "0"))))))))
+                                            << (Scalar << (Int ^ "0"))))))))
                     << (LiteralInit
                         << _(LhsVars) << VarSeq
                         << (AssignInfix
@@ -194,7 +194,7 @@ namespace rego
                                     << (SimpleRef
                                         << (Var ^ item)
                                         << (RefArgBrack
-                                            << (Scalar << (JSONInt ^ "1"))))))))
+                                            << (Scalar << (Int ^ "1"))))))))
                     << _[Tail]));
         },
 
@@ -256,7 +256,7 @@ namespace rego
                                     << (SimpleRef
                                         << (Var ^ item)
                                         << (RefArgBrack
-                                            << (Scalar << (JSONInt ^ "0"))))))))
+                                            << (Scalar << (Int ^ "0"))))))))
                     << (Literal
                         << (Expr
                             << (AssignInfix
@@ -267,7 +267,7 @@ namespace rego
                                             << (Var ^ item)
                                             << (RefArgBrack
                                                 << (Scalar
-                                                    << (JSONInt ^ "1")))))))))
+                                                    << (Int ^ "1")))))))))
                     << _[Tail]));
         },
 
diff --git a/src/passes/if_else.cc b/src/passes/if_else.cc
index cb487696..c8c4aa8c 100644
--- a/src/passes/if_else.cc
+++ b/src/passes/if_else.cc
@@ -36,7 +36,7 @@ namespace rego
 
       In(Group) * (T(Else) * ~T(If) * T(UnifyBody)[UnifyBody]) >>
         [](Match& _) {
-          return Else << (Group << (JSONTrue ^ "true")) << _(UnifyBody);
+          return Else << (Group << (True ^ "true")) << _(UnifyBody);
         },
 
       In(Group) *
diff --git a/src/passes/lift_query.cc b/src/passes/lift_query.cc
index b37498cb..751b236d 100644
--- a/src/passes/lift_query.cc
+++ b/src/passes/lift_query.cc
@@ -17,7 +17,7 @@ namespace rego
                      << (Ref << (RefHead << (Var ^ querymodule)) << RefArgSeq))
                  << (Policy
                      << (RuleComp << (Var ^ queryrule) << Empty << _(Query)
-                                  << (JSONInt ^ "0")));
+                                  << (Int ^ "0")));
         std::ostringstream oss;
         oss << "data." << querymodule.view() << "." << queryrule.view();
         std::string ref = oss.str();
diff --git a/src/passes/lift_to_rule.cc b/src/passes/lift_to_rule.cc
index 078483db..012ec99c 100644
--- a/src/passes/lift_to_rule.cc
+++ b/src/passes/lift_to_rule.cc
@@ -202,7 +202,7 @@ namespace rego
             if (out_map.empty())
             {
               // no outputs. We just return true.
-              rulevalue = DataTerm << (Scalar << JSONTrue);
+              rulevalue = DataTerm << (Scalar << True);
             }
             else
             {
@@ -225,7 +225,7 @@ namespace rego
             Node result = Seq
               << (Lift << DataModule
                        << (RuleFunc << rulename << ruleargs << rulebody
-                                    << rulevalue << (JSONInt ^ "0")))
+                                    << rulevalue << (Int ^ "0")))
               << (UnifyExpr
                   << _(Item)
                   << (Expr << (Enumerate << (Expr << (RefTerm << _(ItemSeq))))))
@@ -284,11 +284,10 @@ namespace rego
                     << (Expr << (_(Compr)->type() << _(Compr) / Var)));
               return Seq << (Lift << DataModule
                                   << (RuleComp << rulename << rulebody
-                                               << rulevalue << (JSONInt ^ "0")))
-                         << (Lift
-                             << DataModule
-                             << (RuleComp << rulename->clone() << Empty
-                                          << default_value << (JSONInt ^ "1")))
+                                               << rulevalue << (Int ^ "0")))
+                         << (Lift << DataModule
+                                  << (RuleComp << rulename->clone() << Empty
+                                               << default_value << (Int ^ "1")))
                          << (UnifyExpr
                              << _(Var)
                              << (Expr << (RefTerm << rulename->clone())));
@@ -314,11 +313,10 @@ namespace rego
               return Seq
                 << (Lift << DataModule
                          << (RuleFunc << rulename << ruleargs << rulebody
-                                      << rulevalue << (JSONInt ^ "0")))
+                                      << rulevalue << (Int ^ "0")))
                 << (Lift << DataModule
                          << (RuleFunc << rulename->clone() << ruleargs->clone()
-                                      << Empty << default_value
-                                      << (JSONInt ^ "1")))
+                                      << Empty << default_value << (Int ^ "1")))
                 << (Local << (Var ^ partial) << Undefined)
                 << (UnifyExpr
                     << (Var ^ partial)
@@ -337,12 +335,12 @@ namespace rego
             find_invars(_(UnifyBody), invars);
 
             Location rulename = _.fresh({"every"});
-            Node rulevalue = DataTerm << (Scalar << (JSONTrue ^ "true"));
+            Node rulevalue = DataTerm << (Scalar << (True ^ "true"));
             if (invars.empty())
             {
               return Seq << (Lift << DataModule
                                   << (RuleComp << (Var ^ rulename) << rulebody
-                                               << rulevalue << (JSONInt ^ "0")))
+                                               << rulevalue << (Int ^ "0")))
                          << (RefTerm << (Var ^ rulename));
             }
 
@@ -357,7 +355,7 @@ namespace rego
             return Seq << (Lift << DataModule
                                 << (RuleFunc << (Var ^ rulename) << ruleargs
                                              << rulebody << rulevalue
-                                             << (JSONInt ^ "0")))
+                                             << (Int ^ "0")))
                        << (ExprCall << (Var ^ rulename) << argseq);
           },
 
diff --git a/src/passes/lists.cc b/src/passes/lists.cc
index 548745a2..c784afb1 100644
--- a/src/passes/lists.cc
+++ b/src/passes/lists.cc
@@ -337,7 +337,8 @@ namespace rego
           return SomeDecl << (VarSeq << group) << (Group << Undefined);
         },
 
-      In(Group) * T(EmptySet) >> ([](Match&) -> Node { return Set; }),
+      In(Group) * T(EmptySet)[EmptySet] >>
+        ([](Match& _) -> Node { return Set ^ _(EmptySet); }),
 
       In(Group) * (T(Square) << End) >> [](Match&) -> Node { return Array; },
 
diff --git a/src/passes/replace_argvals.cc b/src/passes/replace_argvals.cc
index a28c11e6..8412f65e 100644
--- a/src/passes/replace_argvals.cc
+++ b/src/passes/replace_argvals.cc
@@ -55,7 +55,7 @@ namespace
         Node item = unwrap_term(argval->at(i));
         (itemref / RefArgSeq)
           << (RefArgBrack
-              << (Expr << (Term << (Scalar << (JSONInt ^ std::to_string(i))))));
+              << (Expr << (Term << (Scalar << (Int ^ std::to_string(i))))));
         add_constraints(itemref, item, stmts);
       }
     }
diff --git a/src/passes/rulebody.cc b/src/passes/rulebody.cc
index c8f713ae..6635948e 100644
--- a/src/passes/rulebody.cc
+++ b/src/passes/rulebody.cc
@@ -119,577 +119,579 @@ namespace rego
   // <not-expr>.
   PassDef rulebody()
   {
-    PassDef rulebody =
-      {
-        In(UnifyBody) *
-            (T(LiteralWith)
-             << (T(UnifyBody)[UnifyBody] * T(WithSeq)[WithSeq])) >>
-          [](Match& _) { return UnifyExprWith << _(UnifyBody) << _(WithSeq); },
-
-        In(UnifyBody) *
-            (T(LiteralEnum)
-             << (T(Var)[Lhs] * T(Var)[Rhs] * T(UnifyBody)[UnifyBody])) >>
-          [](Match& _) {
-            LOG("enum");
-            Location value = _.fresh({"value"});
-            return Seq << (Lift << UnifyBody
-                                << (Local << (Var ^ value) << Undefined))
-                       << (UnifyExprEnum << (Var ^ value) << _(Lhs) << _(Rhs)
-                                         << _(UnifyBody));
-          },
-
-        // LiteralInit nodes are handled separately. They designate what the
-        // vars are being initialized. There are three basic cases: Arrays,
-        // Objects, and everything else. Arrays and Objects need to be handled
-        // specially because they can have nested variables. For example: [x, 1]
-        // = [2, 1] or
-        // ["a": x, "b": 1] = ["a": 2, "b": 1]
-        // These will get broken down into AssignInfix and BoolInfix nodes.
-        // Everything else simply gets unified.
-
-        // <array> := indexable
-        In(UnifyBody) *
-            (T(LiteralInit)
-             << (T(VarSeq)[LhsVars] * T(VarSeq)[RhsVars]([](auto& n) {
-                   return (*n.first)->size() == 0;
-                 }) *
-                 (T(AssignInfix)
-                  << ((T(AssignArg) << (T(Term) << T(Array)[Lhs])) *
-                      T(AssignArg)[Rhs])))) >>
-          [](Match& _) {
-            LOG("<array> := indexable");
-            Node seq = NodeDef::create(Seq);
-            Node rhs = _(Rhs)->front();
-            if (rhs->type() != RefTerm || rhs->front()->type() != Var)
+    PassDef rulebody = {
+      In(UnifyBody) *
+          (T(LiteralWith) << (T(UnifyBody)[UnifyBody] * T(WithSeq)[WithSeq])) >>
+        [](Match& _) { return UnifyExprWith << _(UnifyBody) << _(WithSeq); },
+
+      In(UnifyBody) *
+          (T(LiteralEnum)
+           << (T(Var)[Lhs] * T(Var)[Rhs] * T(UnifyBody)[UnifyBody])) >>
+        [](Match& _) {
+          LOG("enum");
+          Location value = _.fresh({"value"});
+          return Seq << (Lift << UnifyBody
+                              << (Local << (Var ^ value) << Undefined))
+                     << (UnifyExprEnum << (Var ^ value) << _(Lhs) << _(Rhs)
+                                       << _(UnifyBody));
+        },
+
+      // LiteralInit nodes are handled separately. They designate what the
+      // vars are being initialized. There are three basic cases: Arrays,
+      // Objects, and everything else. Arrays and Objects need to be handled
+      // specially because they can have nested variables. For example: [x, 1]
+      // = [2, 1] or
+      // ["a": x, "b": 1] = ["a": 2, "b": 1]
+      // These will get broken down into AssignInfix and BoolInfix nodes.
+      // Everything else simply gets unified.
+
+      // <array> := indexable
+      In(UnifyBody) *
+          (T(LiteralInit)
+           << (T(VarSeq)[LhsVars] * T(VarSeq)[RhsVars]([](auto& n) {
+                 return (*n.first)->size() == 0;
+               }) *
+               (T(AssignInfix)
+                << ((T(AssignArg) << (T(Term) << T(Array)[Lhs])) *
+                    T(AssignArg)[Rhs])))) >>
+        [](Match& _) {
+          LOG("<array> := indexable");
+          Node seq = NodeDef::create(Seq);
+          Node rhs = _(Rhs)->front();
+          if (rhs->type() != RefTerm || rhs->front()->type() != Var)
+          {
+            // Check if rhs is a var. If not, create a var and set it.
+            Location rhs_loc = _.fresh({"rhs"});
+            seq << (Local << (Var ^ rhs_loc) << Undefined)
+                << (UnifyExpr << (Var ^ rhs_loc) << (Expr << rhs));
+            rhs = Var ^ rhs_loc;
+          }
+          else
+          {
+            rhs = rhs->front();
+          }
+          std::set<Location> vars;
+          for (auto& item : *_(LhsVars))
+          {
+            vars.insert(item->location());
+          }
+
+          // Enumerate the items of lhs.
+          for (std::size_t i = 0; i < _(Lhs)->size(); ++i)
+          {
+            Node item = _(Lhs)->at(i)->front();
+            Node index = Scalar << (Int ^ std::to_string(i));
+            Node rhsval = RefTerm
+              << (SimpleRef << rhs->clone() << (RefArgBrack << index));
+            Node init_vars = NodeDef::create(VarSeq);
+            find_locs_from(item, vars, init_vars);
+            if (init_vars->size() > 0)
             {
-              // Check if rhs is a var. If not, create a var and set it.
-              Location rhs_loc = _.fresh({"rhs"});
-              seq << (Local << (Var ^ rhs_loc) << Undefined)
-                  << (UnifyExpr << (Var ^ rhs_loc) << (Expr << rhs));
-              rhs = Var ^ rhs_loc;
+              // If an item contains mne or more vars from the list, create a
+              // LiteralInit << AssignInfix for that item.
+              seq
+                << (LiteralInit << init_vars << VarSeq
+                                << (AssignInfix << (AssignArg << item)
+                                                << (AssignArg << rhsval)));
             }
             else
             {
-              rhs = rhs->front();
-            }
-            std::set<Location> vars;
-            for (auto& item : *_(LhsVars))
-            {
-              vars.insert(item->location());
-            }
-            // Enumerate the items of lhs.
-            for (std::size_t i = 0; i < _(Lhs)->size(); ++i)
-            {
-              Node item = _(Lhs)->at(i)->front();
-              Node index = Scalar << (JSONInt ^ std::to_string(i));
-              Node rhsval = RefTerm
-                << (SimpleRef << rhs->clone() << (RefArgBrack << index));
-              Node init_vars = NodeDef::create(VarSeq);
-              find_locs_from(item, vars, init_vars);
-              if (init_vars->size() > 0)
-              {
-                // If an item contains mne or more vars from the list, create a
-                // LiteralInit << AssignInfix for that item.
-                seq
-                  << (LiteralInit << init_vars << VarSeq
-                                  << (AssignInfix << (AssignArg << item)
-                                                  << (AssignArg << rhsval)));
-              }
-              else
-              {
-                // Otherwise create a BoolInfix.
-                Location unify = _.fresh({"unify"});
-                seq << (Local << (Var ^ unify) << Undefined)
-                    << (UnifyExpr
-                        << (Var ^ unify)
-                        << (Expr
-                            << (BoolInfix << (BoolArg << item) << Equals
-                                          << (BoolArg << rhsval))));
-              }
-            }
-
-            return seq;
-          },
-
-        // <object> := indexable
-        In(UnifyBody) *
-            (T(LiteralInit)
-             << (T(VarSeq)[LhsVars] * T(VarSeq)[RhsVars]([](auto& n) {
-                   return (*n.first)->size() == 0;
-                 }) *
-                 (T(AssignInfix)
-                  << ((T(AssignArg) << (T(Term) << T(Object)[Lhs])) *
-                      T(AssignArg)[Rhs])))) >>
-          [](Match& _) {
-            LOG("<object> := indexable");
-            Node seq = NodeDef::create(Seq);
-            Node rhs = _(Rhs)->front();
-            if (rhs->type() != RefTerm || rhs->front()->type() != Var)
-            {
-              // Check if rhs is a var. If not, create a var and set it.
-              Location rhs_loc = _.fresh({"rhs"});
-              seq << (Local << (Var ^ rhs_loc) << Undefined)
-                  << (UnifyExpr << (Var ^ rhs_loc) << (Expr << rhs));
-              rhs = Var ^ rhs_loc;
-            }
-            else
-            {
-              rhs = rhs->front();
-            }
-            std::set<Location> vars;
-            for (auto& var : *_(LhsVars))
-            {
-              vars.insert(var->location());
-            }
-            // Enumerate the items of lhs.
-            for (std::size_t i = 0; i < _(Lhs)->size(); ++i)
-            {
-              Node item = _(Lhs)->at(i);
-              Node key = (item / Key);
-              if (key->front()->type() == Term)
-              {
-                key = key->front()->front();
-              }
-
-              Node val = (item / Val)->front();
-              Node rhsval = RefTerm
-                << (SimpleRef << rhs->clone() << (RefArgBrack << key->clone()));
-              Node init_vars = NodeDef::create(VarSeq);
-              find_locs_from(item, vars, init_vars);
-
-              if (init_vars->size() > 0)
-              {
-                // If an item contains one or more vars from the list, create a
-                // LiteralInit << AssignInfix for that item.
-                seq
-                  << (LiteralInit << init_vars << VarSeq
-                                  << (AssignInfix << (AssignArg << val)
-                                                  << (AssignArg << rhsval)));
-              }
-              else
-              {
-                // Otherwise create a Literal << BoolInfix.
-                Location unify = _.fresh({"unify"});
-                seq << (Local << (Var ^ unify) << Undefined)
-                    << (UnifyExpr
-                        << (Var ^ unify)
-                        << (Expr
-                            << (BoolInfix << (BoolArg << val) << Equals
-                                          << (BoolArg << rhsval))));
-              }
-            }
-
-            return seq;
-          },
-
-        // <array> :=: <array>
-        In(UnifyBody) *
-            (T(LiteralInit)
-             << (T(VarSeq)[LhsVars] * T(VarSeq)[RhsVars] *
-                 (T(AssignInfix)
-                  << ((T(AssignArg) << (T(Term) << T(Array)[Lhs])) *
-                      (T(AssignArg) << (T(Term) << T(Array)[Rhs])))))) >>
-          [](Match& _) {
-            LOG("<array> :=: <array>");
-
-            if (_(Lhs)->size() != _(Rhs)->size())
-            {
-              return err(_(Rhs), "Array size mismatch");
-            }
-
-            std::set<Location> lhs_vars;
-            for (auto& var : *_(LhsVars))
-            {
-              lhs_vars.insert(var->location());
-            }
-
-            std::set<Location> rhs_vars;
-            for (auto& var : *_(RhsVars))
-            {
-              rhs_vars.insert(var->location());
-            }
-
-            Node seq = NodeDef::create(Seq);
-            for (std::size_t i = 0; i < _(Lhs)->size(); ++i)
-            {
-              Node lhs_term = _(Lhs)->at(i)->front();
-              Node rhs_term = _(Rhs)->at(i)->front();
-
-              Node lhs_init_vars = NodeDef::create(VarSeq);
-              find_locs_from(lhs_term, lhs_vars, lhs_init_vars);
-
-              Node rhs_init_vars = NodeDef::create(VarSeq);
-              find_locs_from(rhs_term, rhs_vars, rhs_init_vars);
-
-              if (lhs_init_vars->size() > 0 || rhs_init_vars->size() > 0)
-              {
-                seq
-                  << (LiteralInit << lhs_init_vars << rhs_init_vars
-                                  << (AssignInfix << (AssignArg << lhs_term)
-                                                  << (AssignArg << rhs_term)));
-              }
-              else
-              {
-                Location unify = _.fresh({"unify"});
-                seq << (Local << (Var ^ unify) << Undefined)
-                    << (UnifyExpr
-                        << (Var ^ unify)
-                        << (Expr
-                            << (BoolInfix << (BoolArg << lhs_term) << Equals
-                                          << (BoolArg << rhs_term))));
-              }
-            }
-
-            return seq;
-          },
-
-        // <object> :=: <object>
-        In(UnifyBody) *
-            (T(LiteralInit)
-             << (T(VarSeq)[LhsVars] * T(VarSeq)[RhsVars] *
-                 (T(AssignInfix)
-                  << ((T(AssignArg) << (T(Term) << T(Object)[Lhs])) *
-                      (T(AssignArg) << (T(Term) << T(Object)[Rhs])))))) >>
-          [](Match& _) {
-            LOG("<object> :=: <object>");
-            // first, we set up all equalities going lhs <- rhs
-            // so for example, if we have {"a": x, "b": 2, c: 3, "d": 4} = {"a":
-            // 1, "b": y, "c": 3, "d": 4} then this will generate: x =
-            // rhsobj["a"] 2 == rhsobj["b"] 3 == rhsobj[c] 4 == rhsobj["d"] we
-            // then go lhs -> rhs to get the rest: 1 == lhsobj["a"] y =
-            // lhsobj["b"] 3 == lhsobj["c"] 4 == lhsobj["d"] ordering matters
-            // here! unifications need to go first, then boolean checks x =
-            // rhsobj["a"] y = rhsobj["b"] then the boolean checks 1 ==
-            // lhsobj["a"] 2 == rhsobj["b"] 3 == rhsobj[c] 4 == rhsobj["d"] 3 ==
-            // lhsobj["c"] 4 == lhsobj["d"]
-
-            Node lhs = _(Lhs);
-            Node rhs = _(Rhs);
-            if (lhs->size() != rhs->size())
-            {
-              return err(rhs, "Object size mismatch");
+              // Otherwise create a BoolInfix.
+              Location unify = _.fresh({"unify"});
+              seq << (Local << (Var ^ unify) << Undefined)
+                  << (UnifyExpr << (Var ^ unify)
+                                << (Expr
+                                    << (BoolInfix << (BoolArg << item) << Equals
+                                                  << (BoolArg << rhsval))));
             }
-
-            Node seq = NodeDef::create(Seq);
-            Location lhsobj = _.fresh({"lhsobj"});
-            Location rhsobj = _.fresh({"rhsobj"});
-
-            Nodes literalinits;
-            Nodes booleaninfixes;
-
-            std::set<Location> lhs_vars;
-            for (auto& var : *_(LhsVars))
+          }
+
+          if (seq->size() == 0)
+          {
+            return err(_(Lhs), "Invalid initialization: nothing to initialize");
+          }
+
+          return seq;
+        },
+
+      // <object> := indexable
+      In(UnifyBody) *
+          (T(LiteralInit)
+           << (T(VarSeq)[LhsVars] * T(VarSeq)[RhsVars]([](auto& n) {
+                 return (*n.first)->size() == 0;
+               }) *
+               (T(AssignInfix)
+                << ((T(AssignArg) << (T(Term) << T(Object)[Lhs])) *
+                    T(AssignArg)[Rhs])))) >>
+        [](Match& _) {
+          LOG("<object> := indexable");
+          Node seq = NodeDef::create(Seq);
+          Node rhs = _(Rhs)->front();
+          if (rhs->type() != RefTerm || rhs->front()->type() != Var)
+          {
+            // Check if rhs is a var. If not, create a var and set it.
+            Location rhs_loc = _.fresh({"rhs"});
+            seq << (Local << (Var ^ rhs_loc) << Undefined)
+                << (UnifyExpr << (Var ^ rhs_loc) << (Expr << rhs));
+            rhs = Var ^ rhs_loc;
+          }
+          else
+          {
+            rhs = rhs->front();
+          }
+          std::set<Location> vars;
+          for (auto& var : *_(LhsVars))
+          {
+            vars.insert(var->location());
+          }
+
+          // Enumerate the items of lhs.
+          for (std::size_t i = 0; i < _(Lhs)->size(); ++i)
+          {
+            Node item = _(Lhs)->at(i);
+            Node key = (item / Key);
+            if (key->front()->type() == Term)
             {
-              lhs_vars.insert(var->location());
+              key = key->front()->front();
             }
 
-            std::set<Location> rhs_vars;
-            for (auto& var : *_(RhsVars))
-            {
-              rhs_vars.insert(var->location());
-            }
+            Node val = (item / Val)->front();
+            Node rhsval = RefTerm
+              << (SimpleRef << rhs->clone() << (RefArgBrack << key->clone()));
+            Node init_vars = NodeDef::create(VarSeq);
+            find_locs_from(item, vars, init_vars);
 
-            add_object_comparisons(
-              lhsobj,
-              lhs,
-              lhs_vars,
-              rhs,
-              rhs_vars,
-              literalinits,
-              booleaninfixes);
-            add_object_comparisons(
-              rhsobj,
-              rhs,
-              rhs_vars,
-              lhs,
-              lhs_vars,
-              literalinits,
-              booleaninfixes);
-
-            for (auto item : literalinits)
+            if (init_vars->size() > 0)
             {
-              seq << item;
+              // If an item contains one or more vars from the list, create a
+              // LiteralInit << AssignInfix for that item.
+              seq
+                << (LiteralInit << init_vars << VarSeq
+                                << (AssignInfix << (AssignArg << val)
+                                                << (AssignArg << rhsval)));
             }
-
-            seq << (Local << (Var ^ lhsobj) << Undefined)
-                << (Local << (Var ^ rhsobj) << Undefined)
-                << (UnifyExpr << (Var ^ lhsobj) << (Expr << (Term << _(Lhs))))
-                << (UnifyExpr << (Var ^ rhsobj) << (Expr << (Term << _(Rhs))));
-
-            for (auto item : booleaninfixes)
+            else
             {
+              // Otherwise create a Literal << BoolInfix.
               Location unify = _.fresh({"unify"});
               seq << (Local << (Var ^ unify) << Undefined)
-                  << (UnifyExpr << (Var ^ unify) << (Expr << item));
+                  << (UnifyExpr << (Var ^ unify)
+                                << (Expr
+                                    << (BoolInfix << (BoolArg << val) << Equals
+                                                  << (BoolArg << rhsval))));
             }
-
-            return seq;
-          },
-
-        In(UnifyBody) *
-            (T(LiteralInit)
-             << (T(VarSeq)[LhsVars](
-                   [](auto& n) { return (*n.first)->size() == 0; }) *
-                 T(VarSeq)[RhsVars](
-                   [](auto& n) { return (*n.first)->size() > 0; }) *
-                 (T(AssignInfix)
-                  << (T(AssignArg)[Lhs] * T(AssignArg)[Rhs])))) >>
-          [](Match& _) {
-            return LiteralInit << _(RhsVars) << _(LhsVars)
-                               << (AssignInfix << _(Rhs) << _(Lhs));
-          },
-
-        In(UnifyBody) *
-            (T(LiteralInit)
-             << (T(VarSeq)[LhsVars](
-                   [](auto& n) { return (*n.first)->size() > 0; }) *
-                 T(VarSeq)[RhsVars](
-                   [](auto& n) { return (*n.first)->size() == 0; }) *
-                 (T(AssignInfix)
-                  << ((T(AssignArg) << (T(RefTerm) << T(Var)[Lhs])) *
-                      T(AssignArg)[Rhs])))) >>
-          [](Match& _) {
-            // eventually, most init statements will reduce down
-            // to this.
-            return UnifyExpr << _(Lhs) << (Expr << _(Rhs)->front());
-          },
-
-        In(UnifyBody) *
-            (T(LiteralInit)
-             << (T(VarSeq)[LhsVars] * T(VarSeq)[RhsVars] *
-                 (T(AssignInfix)
-                  << ((T(AssignArg) << (T(RefTerm) << T(Var)[Lhs])) *
-                      T(AssignArg)[Rhs])))) >>
-          [](Match& _) {
-            // this occurs when there is a loop in the init. This is allowed,
-            // so we unify, but we may want to warn the user.
-            return UnifyExpr << _(Lhs) << (Expr << _(Rhs)->front());
-          },
-
-        In(UnifyBody) *
-            (T(LiteralInit)
-             << (T(VarSeq)[LhsVars] * T(VarSeq)[RhsVars] *
-                 (T(AssignInfix)
-                  << (T(AssignArg)[Lhs] * (T(RefTerm) << T(Var)[Rhs]))))) >>
-          [](Match& _) {
-            // this occurs when there is a loop in the init. This is allowed,
-            // so we unify, but we may want to warn the user.
-            return UnifyExpr << _(Rhs) << (Expr << _(Lhs)->front());
-          },
-
-        In(UnifyBody) *
-            (T(Literal) << ((T(Expr) << T(AssignInfix)[AssignInfix]))) >>
-          [](Match& _) { return _(AssignInfix); },
-
-        In(With) * T(Expr)[Expr]([](auto& n) {
-          return is_in(*n.first, {UnifyBody});
-        }) >>
-          [](Match& _) {
-            LOG("with");
-            Location temp = _.fresh({"with"});
-            return Seq << (Lift << UnifyBody
-                                << (Local << (Var ^ temp) << Undefined))
-                       << (Lift << UnifyBody
-                                << (UnifyExpr << (Var ^ temp) << _(Expr)))
-                       << (Var ^ temp);
-          },
-
-        // <expr>
-        In(UnifyBody) * (T(Literal) << T(Expr)[Expr]) >>
-          [](Match& _) {
-            std::string prefix = in_query(_(Expr)) ? "value" : "unify";
-            Location temp = _.fresh({prefix});
-            return Seq << (Local << (Var ^ temp) << Undefined)
-                       << (UnifyExpr << (Var ^ temp) << _(Expr));
-          },
-
-        // <any> = <any>
-        In(UnifyBody) *
-            (T(AssignInfix) << (T(AssignArg)[Lhs] * T(AssignArg)[Rhs])) >>
-          [](Match& _) {
-            LOG("<any> = <any>");
-            Node seq = NodeDef::create(Seq);
-            Location unify = _.fresh({"unify"});
-            return Seq << (Local << (Var ^ unify) << Undefined)
-                       << (UnifyExpr
-                           << (Var ^ unify)
-                           << (Expr
-                               << (BoolInfix << (BoolArg << _(Lhs)->front())
-                                             << Equals
-                                             << (BoolArg << _(Rhs)->front()))));
-          },
-
-        // not any = any
-        In(UnifyBody) *
-            (T(LiteralNot)
-             << (T(Expr)
-                 << (T(AssignInfix)
-                     << (T(AssignArg)[Lhs] * T(AssignArg)[Rhs])))) >>
-          [](Match& _) {
-            LOG("not any = any");
-            Location unify = _.fresh({"unify"});
-            return Seq << (Local << (Var ^ unify) << Undefined)
-                       << (UnifyExpr
-                           << (Var ^ unify)
-                           << (Expr
-                               << (BoolInfix << (BoolArg << _(Lhs)->front())
-                                             << NotEquals
-                                             << (BoolArg << _(Rhs)->front()))));
-          },
-
-        // <notexpr>
-        In(UnifyBody) * (T(LiteralNot) << T(UnifyBody)[UnifyBody]) >>
-          [](Match& _) { return UnifyExprNot << _(UnifyBody); },
-
-        // <array> = <array>
-        In(UnifyBody) *
-            (T(AssignInfix)
-             << ((T(AssignArg) << (T(Term) << T(Array)[Lhs])) *
-                 (T(AssignArg) << (T(Term) << T(Array)[Rhs])))) >>
-          [](Match& _) {
-            LOG("<array> = <array>");
-            Node lhs = _(Lhs);
-            Node rhs = _(Rhs);
-            if (lhs->size() != rhs->size())
+          }
+
+          if (seq->size() == 0)
+          {
+            return err(_(Lhs), "Invalid initialization: nothing to initialize");
+          }
+
+          return seq;
+        },
+
+      // <array> :=: <array>
+      In(UnifyBody) *
+          (T(LiteralInit)
+           << (T(VarSeq)[LhsVars] * T(VarSeq)[RhsVars] *
+               (T(AssignInfix)
+                << ((T(AssignArg) << (T(Term) << T(Array)[Lhs])) *
+                    (T(AssignArg) << (T(Term) << T(Array)[Rhs])))))) >>
+        [](Match& _) {
+          LOG("<array> :=: <array>");
+
+          if (_(Lhs)->size() != _(Rhs)->size())
+          {
+            return err(_(Rhs), "Array size mismatch");
+          }
+
+          std::set<Location> lhs_vars;
+          for (auto& var : *_(LhsVars))
+          {
+            lhs_vars.insert(var->location());
+          }
+
+          std::set<Location> rhs_vars;
+          for (auto& var : *_(RhsVars))
+          {
+            rhs_vars.insert(var->location());
+          }
+
+          Node seq = NodeDef::create(Seq);
+          for (std::size_t i = 0; i < _(Lhs)->size(); ++i)
+          {
+            Node lhs_term = _(Lhs)->at(i)->front();
+            Node rhs_term = _(Rhs)->at(i)->front();
+
+            Node lhs_init_vars = NodeDef::create(VarSeq);
+            find_locs_from(lhs_term, lhs_vars, lhs_init_vars);
+
+            Node rhs_init_vars = NodeDef::create(VarSeq);
+            find_locs_from(rhs_term, rhs_vars, rhs_init_vars);
+
+            if (lhs_init_vars->size() > 0 || rhs_init_vars->size() > 0)
             {
-              return err(_(Lhs), "Array size mismatch");
+              seq
+                << (LiteralInit << lhs_init_vars << rhs_init_vars
+                                << (AssignInfix << (AssignArg << lhs_term)
+                                                << (AssignArg << rhs_term)));
             }
-
-            Location unify = _.fresh({"unify"});
-            return Seq << (Local << (Var ^ unify) << Undefined)
-                       << (UnifyExpr
-                           << (Var ^ unify)
-                           << (Expr
-                               << (BoolInfix << (BoolArg << (Term << lhs))
-                                             << Equals
-                                             << (BoolArg << (Term << rhs)))));
-          },
-
-        // <object> = <object>
-        In(UnifyBody) *
-            (T(AssignInfix)
-             << ((T(AssignArg) << (T(Term) << T(Object)[Lhs])) *
-                 (T(AssignArg) << (T(Term) << T(Object)[Rhs])))) >>
-          [](Match& _) {
-            LOG("<object> = <object>");
-
-            Node lhs = _(Lhs);
-            Node rhs = _(Rhs);
-            if (lhs->size() != rhs->size())
+            else
             {
-              return err(rhs, "Object size mismatch");
+              Location unify = _.fresh({"unify"});
+              seq << (Local << (Var ^ unify) << Undefined)
+                  << (UnifyExpr
+                      << (Var ^ unify)
+                      << (Expr
+                          << (BoolInfix << (BoolArg << lhs_term) << Equals
+                                        << (BoolArg << rhs_term))));
             }
-
+          }
+
+          if (seq->size() == 0)
+          {
+            return err(_(Lhs), "Invalid initialization: nothing to initialize");
+          }
+
+          return seq;
+        },
+
+      // <object> :=: <object>
+      In(UnifyBody) *
+          (T(LiteralInit)
+           << (T(VarSeq)[LhsVars] * T(VarSeq)[RhsVars] *
+               (T(AssignInfix)
+                << ((T(AssignArg) << (T(Term) << T(Object)[Lhs])) *
+                    (T(AssignArg) << (T(Term) << T(Object)[Rhs])))))) >>
+        [](Match& _) {
+          LOG("<object> :=: <object>");
+          // first, we set up all equalities going lhs <- rhs
+          // so for example, if we have {"a": x, "b": 2, c: 3, "d": 4} = {"a":
+          // 1, "b": y, "c": 3, "d": 4} then this will generate: x =
+          // rhsobj["a"] 2 == rhsobj["b"] 3 == rhsobj[c] 4 == rhsobj["d"] we
+          // then go lhs -> rhs to get the rest: 1 == lhsobj["a"] y =
+          // lhsobj["b"] 3 == lhsobj["c"] 4 == lhsobj["d"] ordering matters
+          // here! unifications need to go first, then boolean checks x =
+          // rhsobj["a"] y = rhsobj["b"] then the boolean checks 1 ==
+          // lhsobj["a"] 2 == rhsobj["b"] 3 == rhsobj[c] 4 == rhsobj["d"] 3 ==
+          // lhsobj["c"] 4 == lhsobj["d"]
+
+          Node lhs = _(Lhs);
+          Node rhs = _(Rhs);
+          if (lhs->size() != rhs->size())
+          {
+            return err(rhs, "Object size mismatch");
+          }
+
+          Node seq = NodeDef::create(Seq);
+          Location lhsobj = _.fresh({"lhsobj"});
+          Location rhsobj = _.fresh({"rhsobj"});
+
+          Nodes literalinits;
+          Nodes booleaninfixes;
+
+          std::set<Location> lhs_vars;
+          for (auto& var : *_(LhsVars))
+          {
+            lhs_vars.insert(var->location());
+          }
+
+          std::set<Location> rhs_vars;
+          for (auto& var : *_(RhsVars))
+          {
+            rhs_vars.insert(var->location());
+          }
+
+          add_object_comparisons(
+            lhsobj, lhs, lhs_vars, rhs, rhs_vars, literalinits, booleaninfixes);
+          add_object_comparisons(
+            rhsobj, rhs, rhs_vars, lhs, lhs_vars, literalinits, booleaninfixes);
+
+          for (auto item : literalinits)
+          {
+            seq << item;
+          }
+
+          seq << (Local << (Var ^ lhsobj) << Undefined)
+              << (Local << (Var ^ rhsobj) << Undefined)
+              << (UnifyExpr << (Var ^ lhsobj) << (Expr << (Term << _(Lhs))))
+              << (UnifyExpr << (Var ^ rhsobj) << (Expr << (Term << _(Rhs))));
+
+          for (auto item : booleaninfixes)
+          {
             Location unify = _.fresh({"unify"});
-            return Seq << (Local << (Var ^ unify) << Undefined)
-                       << (UnifyExpr
-                           << (Var ^ unify)
-                           << (Expr
-                               << (BoolInfix << (BoolArg << (Term << lhs))
-                                             << Equals
-                                             << (BoolArg << (Term << rhs)))));
-          },
-
-        In(UnifyBody) * (T(LiteralEnum) << T(UnifyExpr)[UnifyExpr]) >>
-          [](Match& _) { return _(UnifyExpr); },
-
-        // <compr>
-        In(UnifyBody) *
-            (T(UnifyExpr)
-             << (T(Var)[Var] *
-                 (T(Expr)
-                  << (T(Term)
-                      << (T(ArrayCompr) / T(SetCompr) /
-                          T(ObjectCompr))[Compr])))) >>
-          [](Match& _) {
-            LOG("<compr>");
-            return UnifyExprCompr << _(Var)
-                                  << (_(Compr)->type() << (_(Compr) / Var))
-                                  << (_(Compr) / NestedBody);
-          },
-
-        // <compr>
-        In(UnifyBody) *
-            (T(UnifyExpr)
-             << (T(Var)[Var] *
-                 (T(Expr)
-                  << (T(ArrayCompr) / T(SetCompr) / T(ObjectCompr))[Compr]))) >>
-          [](Match& _) {
-            LOG("<compr>");
-            return UnifyExprCompr << _(Var)
-                                  << (_(Compr)->type() << (_(Compr) / Var))
-                                  << (_(Compr) / NestedBody);
-          },
-
-        // <compr> (other)
-        T(Term) << (T(ArrayCompr) / T(SetCompr) / T(ObjectCompr))[Compr](
-          [](auto& n) { return is_in(*n.first, {UnifyBody}); }) >>
-          [](Match& _) {
-            LOG("<compr> (other)");
-            Location term = _.fresh({"term"});
-            return Seq << (Lift << UnifyBody
-                                << (Local << (Var ^ term) << Undefined))
-                       << (Lift
-                           << UnifyBody
-                           << (UnifyExpr << (Var ^ term) << (Expr << _(Compr))))
-                       << (RefTerm << (Var ^ term));
-          },
-
-        // <binarg>.<setcompr>
-        In(BinArg) * T(SetCompr)[SetCompr]([](auto& n) {
-          return is_in(*n.first, {UnifyBody});
-        }) >>
-          [](Match& _) {
-            LOG("<binarg>.<setcompr>");
-            Location set = _.fresh({"setcompr"});
-            return Seq << (Lift << UnifyBody
-                                << (Local << (Var ^ set) << Undefined))
-                       << (Lift << UnifyBody
-                                << (UnifyExpr << (Var ^ set)
-                                              << (Expr << _(SetCompr))))
-                       << (RefTerm << (Var ^ set));
-          },
-
-        In(RefArgBrack) * T(NumTerm)[NumTerm] >>
-          [](Match& _) { return Scalar << _(NumTerm)->front(); },
-
-        // errors
-
-        In(BoolArg) * T(BoolInfix)[BoolInfix] >>
-          [](Match& _) {
-            return err(_(BoolInfix), "Invalid boolean expression");
-          },
-
-        In(Term, BinArg) * T(SetCompr)[SetCompr] >>
-          [](Match& _) {
-            return err(_(SetCompr), "Invalid set comprehension");
-          },
-
-        In(Term) * T(ArrayCompr)[ArrayCompr] >>
-          [](Match& _) {
-            return err(_(ArrayCompr), "Invalid array comprehension");
-          },
-
-        In(Term) * T(ObjectCompr)[ObjectCompr] >>
-          [](Match& _) {
-            return err(_(ObjectCompr), "Invalid object comprehension");
-          },
-
-        In(ObjectItem) * (T(Expr)[Expr] << T(AssignInfix)) >>
-          [](Match& _) { return err(_(Expr), "Invalid object item"); },
-
-        In(UnifyBody) * T(AssignInfix)[AssignInfix] >>
-          [](Match& _) { return err(_(AssignInfix), "Invalid assignment"); },
-
-        In(Expr) * T(AssignInfix)[AssignInfix] >>
-          [](Match& _) { return err(_(AssignInfix), "Invalid assignment"); },
-
-        In(BoolArg) * (T(Membership) / T(AssignInfix))[Arg] >>
-          [](Match& _) { return err(_(Arg), "Invalid boolean argument"); },
-
-        In(RefArgBrack) * (T(Membership) / T(AssignInfix))[Arg] >>
-          [](Match& _) { return err(_(Arg), "Invalid index"); },
-      };
+            seq << (Local << (Var ^ unify) << Undefined)
+                << (UnifyExpr << (Var ^ unify) << (Expr << item));
+          }
+
+          if (seq->size() == 0)
+          {
+            return err(_(Lhs), "Invalid initialization: nothing to initialize");
+          }
+
+          return seq;
+        },
+
+      In(UnifyBody) *
+          (T(LiteralInit)
+           << (T(VarSeq)[LhsVars](
+                 [](auto& n) { return (*n.first)->size() == 0; }) *
+               T(VarSeq)[RhsVars](
+                 [](auto& n) { return (*n.first)->size() > 0; }) *
+               (T(AssignInfix) << (T(AssignArg)[Lhs] * T(AssignArg)[Rhs])))) >>
+        [](Match& _) {
+          return LiteralInit << _(RhsVars) << _(LhsVars)
+                             << (AssignInfix << _(Rhs) << _(Lhs));
+        },
+
+      In(UnifyBody) *
+          (T(LiteralInit)
+           << (T(VarSeq)[LhsVars](
+                 [](auto& n) { return (*n.first)->size() > 0; }) *
+               T(VarSeq)[RhsVars](
+                 [](auto& n) { return (*n.first)->size() == 0; }) *
+               (T(AssignInfix)
+                << ((T(AssignArg) << (T(RefTerm) << T(Var)[Lhs])) *
+                    T(AssignArg)[Rhs])))) >>
+        [](Match& _) {
+          // eventually, most init statements will reduce down
+          // to this.
+          return UnifyExpr << _(Lhs) << (Expr << _(Rhs)->front());
+        },
+
+      In(UnifyBody) *
+          (T(LiteralInit)
+           << (T(VarSeq)[LhsVars] * T(VarSeq)[RhsVars] *
+               (T(AssignInfix)
+                << ((T(AssignArg) << (T(RefTerm) << T(Var)[Lhs])) *
+                    T(AssignArg)[Rhs])))) >>
+        [](Match& _) {
+          // this occurs when there is a loop in the init. This is allowed,
+          // so we unify, but we may want to warn the user.
+          return UnifyExpr << _(Lhs) << (Expr << _(Rhs)->front());
+        },
+
+      In(UnifyBody) *
+          (T(LiteralInit)
+           << (T(VarSeq)[LhsVars] * T(VarSeq)[RhsVars] *
+               (T(AssignInfix)
+                << (T(AssignArg)[Lhs] * (T(RefTerm) << T(Var)[Rhs]))))) >>
+        [](Match& _) {
+          // this occurs when there is a loop in the init. This is allowed,
+          // so we unify, but we may want to warn the user.
+          return UnifyExpr << _(Rhs) << (Expr << _(Lhs)->front());
+        },
+
+      In(UnifyBody) *
+          (T(Literal) << ((T(Expr) << T(AssignInfix)[AssignInfix]))) >>
+        [](Match& _) { return _(AssignInfix); },
+
+      In(With) *
+          T(Expr)[Expr]([](auto& n) { return is_in(*n.first, {UnifyBody}); }) >>
+        [](Match& _) {
+          LOG("with");
+          Location temp = _.fresh({"with"});
+          return Seq << (Lift << UnifyBody
+                              << (Local << (Var ^ temp) << Undefined))
+                     << (Lift << UnifyBody
+                              << (UnifyExpr << (Var ^ temp) << _(Expr)))
+                     << (Var ^ temp);
+        },
+
+      // <expr>
+      In(UnifyBody) * (T(Literal) << T(Expr)[Expr]) >>
+        [](Match& _) {
+          std::string prefix = in_query(_(Expr)) ? "value" : "unify";
+          Location temp = _.fresh({prefix});
+          return Seq << (Local << (Var ^ temp) << Undefined)
+                     << (UnifyExpr << (Var ^ temp) << _(Expr));
+        },
+
+      // <any> = <any>
+      In(UnifyBody) *
+          (T(AssignInfix) << (T(AssignArg)[Lhs] * T(AssignArg)[Rhs])) >>
+        [](Match& _) {
+          LOG("<any> = <any>");
+          Node seq = NodeDef::create(Seq);
+          Location unify = _.fresh({"unify"});
+          return Seq << (Local << (Var ^ unify) << Undefined)
+                     << (UnifyExpr
+                         << (Var ^ unify)
+                         << (Expr
+                             << (BoolInfix << (BoolArg << _(Lhs)->front())
+                                           << Equals
+                                           << (BoolArg << _(Rhs)->front()))));
+        },
+
+      // not any = any
+      In(UnifyBody) *
+          (T(LiteralNot)
+           << (T(Expr)
+               << (T(AssignInfix)
+                   << (T(AssignArg)[Lhs] * T(AssignArg)[Rhs])))) >>
+        [](Match& _) {
+          LOG("not any = any");
+          Location unify = _.fresh({"unify"});
+          return Seq << (Local << (Var ^ unify) << Undefined)
+                     << (UnifyExpr
+                         << (Var ^ unify)
+                         << (Expr
+                             << (BoolInfix << (BoolArg << _(Lhs)->front())
+                                           << NotEquals
+                                           << (BoolArg << _(Rhs)->front()))));
+        },
+
+      // <notexpr>
+      In(UnifyBody) * (T(LiteralNot) << T(UnifyBody)[UnifyBody]) >>
+        [](Match& _) { return UnifyExprNot << _(UnifyBody); },
+
+      // <array> = <array>
+      In(UnifyBody) *
+          (T(AssignInfix)
+           << ((T(AssignArg) << (T(Term) << T(Array)[Lhs])) *
+               (T(AssignArg) << (T(Term) << T(Array)[Rhs])))) >>
+        [](Match& _) {
+          LOG("<array> = <array>");
+          Node lhs = _(Lhs);
+          Node rhs = _(Rhs);
+          if (lhs->size() != rhs->size())
+          {
+            return err(_(Lhs), "Array size mismatch");
+          }
+
+          Location unify = _.fresh({"unify"});
+          return Seq << (Local << (Var ^ unify) << Undefined)
+                     << (UnifyExpr
+                         << (Var ^ unify)
+                         << (Expr
+                             << (BoolInfix << (BoolArg << (Term << lhs))
+                                           << Equals
+                                           << (BoolArg << (Term << rhs)))));
+        },
+
+      // <object> = <object>
+      In(UnifyBody) *
+          (T(AssignInfix)
+           << ((T(AssignArg) << (T(Term) << T(Object)[Lhs])) *
+               (T(AssignArg) << (T(Term) << T(Object)[Rhs])))) >>
+        [](Match& _) {
+          LOG("<object> = <object>");
+
+          Node lhs = _(Lhs);
+          Node rhs = _(Rhs);
+          if (lhs->size() != rhs->size())
+          {
+            return err(rhs, "Object size mismatch");
+          }
+
+          Location unify = _.fresh({"unify"});
+          return Seq << (Local << (Var ^ unify) << Undefined)
+                     << (UnifyExpr
+                         << (Var ^ unify)
+                         << (Expr
+                             << (BoolInfix << (BoolArg << (Term << lhs))
+                                           << Equals
+                                           << (BoolArg << (Term << rhs)))));
+        },
+
+      In(UnifyBody) * (T(LiteralEnum) << T(UnifyExpr)[UnifyExpr]) >>
+        [](Match& _) { return _(UnifyExpr); },
+
+      // <compr>
+      In(UnifyBody) *
+          (T(UnifyExpr)
+           << (T(Var)[Var] *
+               (T(Expr)
+                << (T(Term)
+                    << (T(ArrayCompr) / T(SetCompr) /
+                        T(ObjectCompr))[Compr])))) >>
+        [](Match& _) {
+          LOG("<compr>");
+          return UnifyExprCompr << _(Var)
+                                << (_(Compr)->type() << (_(Compr) / Var))
+                                << (_(Compr) / NestedBody);
+        },
+
+      // <compr>
+      In(UnifyBody) *
+          (T(UnifyExpr)
+           << (T(Var)[Var] *
+               (T(Expr)
+                << (T(ArrayCompr) / T(SetCompr) / T(ObjectCompr))[Compr]))) >>
+        [](Match& _) {
+          LOG("<compr>");
+          return UnifyExprCompr << _(Var)
+                                << (_(Compr)->type() << (_(Compr) / Var))
+                                << (_(Compr) / NestedBody);
+        },
+
+      // <compr> (other)
+      T(Term) << (T(ArrayCompr) / T(SetCompr) / T(ObjectCompr))[Compr](
+        [](auto& n) { return is_in(*n.first, {UnifyBody}); }) >>
+        [](Match& _) {
+          LOG("<compr> (other)");
+          Location term = _.fresh({"term"});
+          return Seq << (Lift << UnifyBody
+                              << (Local << (Var ^ term) << Undefined))
+                     << (Lift
+                         << UnifyBody
+                         << (UnifyExpr << (Var ^ term) << (Expr << _(Compr))))
+                     << (RefTerm << (Var ^ term));
+        },
+
+      // <binarg>.<setcompr>
+      In(BinArg) * T(SetCompr)[SetCompr]([](auto& n) {
+        return is_in(*n.first, {UnifyBody});
+      }) >>
+        [](Match& _) {
+          LOG("<binarg>.<setcompr>");
+          Location set = _.fresh({"setcompr"});
+          return Seq << (Lift << UnifyBody
+                              << (Local << (Var ^ set) << Undefined))
+                     << (Lift
+                         << UnifyBody
+                         << (UnifyExpr << (Var ^ set) << (Expr << _(SetCompr))))
+                     << (RefTerm << (Var ^ set));
+        },
+
+      In(RefArgBrack) * T(NumTerm)[NumTerm] >>
+        [](Match& _) { return Scalar << _(NumTerm)->front(); },
+
+      // errors
+
+      In(BoolArg) * T(BoolInfix)[BoolInfix] >>
+        [](Match& _) {
+          return err(_(BoolInfix), "Invalid boolean expression");
+        },
+
+      In(Term, BinArg) * T(SetCompr)[SetCompr] >>
+        [](Match& _) { return err(_(SetCompr), "Invalid set comprehension"); },
+
+      In(Term) * T(ArrayCompr)[ArrayCompr] >>
+        [](Match& _) {
+          return err(_(ArrayCompr), "Invalid array comprehension");
+        },
+
+      In(Term) * T(ObjectCompr)[ObjectCompr] >>
+        [](Match& _) {
+          return err(_(ObjectCompr), "Invalid object comprehension");
+        },
+
+      In(ObjectItem) * (T(Expr)[Expr] << T(AssignInfix)) >>
+        [](Match& _) { return err(_(Expr), "Invalid object item"); },
+
+      In(UnifyBody) * T(AssignInfix)[AssignInfix] >>
+        [](Match& _) { return err(_(AssignInfix), "Invalid assignment"); },
+
+      In(Expr) * T(AssignInfix)[AssignInfix] >>
+        [](Match& _) { return err(_(AssignInfix), "Invalid assignment"); },
+
+      In(BoolArg) * (T(Membership) / T(AssignInfix))[Arg] >>
+        [](Match& _) { return err(_(Arg), "Invalid boolean argument"); },
+
+      In(RefArgBrack) * (T(Membership) / T(AssignInfix))[Arg] >>
+        [](Match& _) { return err(_(Arg), "Invalid index"); },
+    };
 
     rulebody.post(UnifyBody, [](Node n) {
       for (auto child : *n)
diff --git a/src/passes/rules.cc b/src/passes/rules.cc
index 21d5ed12..2e44aa7c 100644
--- a/src/passes/rules.cc
+++ b/src/passes/rules.cc
@@ -45,7 +45,7 @@ namespace rego
            << (T(Var)[Id] * (T(Array) << (T(Group)[Item] * End)) *
                T(UnifyBody)[UnifyBody])) >>
         [](Match& _) {
-          return Rule << JSONFalse
+          return Rule << False
                       << (RuleHead << (RuleRef << _(Id))
                                    << (RuleHeadSet << _(Item)))
                       << _(UnifyBody) << ElseSeq;
@@ -58,11 +58,11 @@ namespace rego
         [](Match& _) {
           // this has the form of a set rule but the reference implementation
           // interprets it as an object rule instead.
-          return Rule << JSONFalse
+          return Rule << False
                       << (RuleHead << (RuleRef << _(Id))
                                    << (RuleHeadObj
                                        << _(Item) << (AssignOperator << Assign)
-                                       << (Group << (JSONTrue ^ "true"))))
+                                       << (Group << (True ^ "true"))))
                       << _(UnifyBody) << ElseSeq;
         },
 
@@ -70,7 +70,7 @@ namespace rego
           (T(Group)
            << (T(Var)[Id] * (T(Array) << (T(Group)[Item] * End)) * End)) >>
         [](Match& _) {
-          return Rule << JSONFalse
+          return Rule << False
                       << (RuleHead << (RuleRef << _(Id))
                                    << (RuleHeadSet << _(Item)))
                       << Empty << ElseSeq;
@@ -82,7 +82,7 @@ namespace rego
                (T(Assign) / T(Unify)) * ExprToken[Head] * ExprToken++[Tail] *
                ~T(If) * T(UnifyBody)[UnifyBody])) >>
         [](Match& _) {
-          return Rule << JSONFalse
+          return Rule << False
                       << (RuleHead << (RuleRef << _(Id))
                                    << (RuleHeadObj
                                        << _(Key) << (AssignOperator << Assign)
@@ -95,7 +95,7 @@ namespace rego
            << (T(Var)[Id] * (T(Array) << (T(Group)[Key] * End)) *
                (T(Assign) / T(Unify)) * ExprToken[Head] * ExprToken++[Tail])) >>
         [](Match& _) {
-          return Rule << JSONFalse
+          return Rule << False
                       << (RuleHead << (RuleRef << _(Id))
                                    << (RuleHeadObj
                                        << _(Key) << (AssignOperator << Assign)
@@ -108,8 +108,8 @@ namespace rego
            << (RuleRefToken[RefHead] * RuleRefToken++[RefArgSeq] * ~T(If) *
                T(UnifyBody)[UnifyBody] * (T(Else) / T(UnifyBody))++[Else])) >>
         [](Match& _) {
-          Node value = Group << JSONTrue;
-          return Rule << JSONFalse
+          Node value = Group << True;
+          return Rule << False
                       << (RuleHead << (RuleRef << _(RefHead) << _[RefArgSeq])
                                    << (RuleHeadComp
                                        << (AssignOperator << Assign) << value))
@@ -124,7 +124,7 @@ namespace rego
                (T(Else) / T(UnifyBody))++[Else])) >>
         [](Match& _) {
           Node value = (Group << _(Head) << _[Tail]);
-          return Rule << JSONFalse
+          return Rule << False
                       << (RuleHead << (RuleRef << _(RefHead) << _[RefArgSeq])
                                    << (RuleHeadComp
                                        << (AssignOperator << Assign) << value))
@@ -137,7 +137,7 @@ namespace rego
                RuleRefToken++[RefArgSeq] * (T(Assign) / T(Unify)) * ~T(If) *
                ExprToken[Head] * ExprToken++[Tail])) >>
         [](Match& _) {
-          Node is_default = _(Default) != nullptr ? JSONTrue : JSONFalse;
+          Node is_default = _(Default) != nullptr ? True : False;
           return Rule << is_default
                       << (RuleHead
                           << (RuleRef << _(RefHead) << _[RefArgSeq])
@@ -153,7 +153,7 @@ namespace rego
                T(UnifyBody)[UnifyBody])) >>
         [](Match& _) {
           // a misclassified single-element set
-          Node is_default = _(Default) != nullptr ? JSONTrue : JSONFalse;
+          Node is_default = _(Default) != nullptr ? True : False;
           return Rule << is_default
                       << (RuleHead << (RuleRef << _(RefHead) << _[RefArgSeq])
                                    << (RuleHeadComp
@@ -186,8 +186,8 @@ namespace rego
             }
           }
 
-          Node value = Group << JSONTrue;
-          return Rule << JSONFalse
+          Node value = Group << True;
+          return Rule << False
                       << (RuleHead
                           << (RuleRef << _(RefHead) << _[RefArgSeq])
                           << (RuleHeadFunc << args << (AssignOperator << Assign)
@@ -221,7 +221,7 @@ namespace rego
           }
 
           Node value = Group << _(Head) << _[Tail];
-          return Rule << JSONFalse
+          return Rule << False
                       << (RuleHead
                           << (RuleRef << _(RefHead) << _[RefArgSeq])
                           << (RuleHeadFunc << args << (AssignOperator << Assign)
@@ -254,7 +254,7 @@ namespace rego
             }
           }
 
-          Node is_default = _(Default) != nullptr ? JSONTrue : JSONFalse;
+          Node is_default = _(Default) != nullptr ? True : False;
           Node value = Group << _(Head) << _[Tail];
           return Rule << is_default
                       << (RuleHead
@@ -270,7 +270,7 @@ namespace rego
                ExprToken[Head] * ExprToken++[Tail] * ~T(If) *
                T(UnifyBody)[UnifyBody])) >>
         [](Match& _) {
-          return Rule << JSONFalse
+          return Rule << False
                       << (RuleHead
                           << (RuleRef << _(RefHead) << _[RefArgSeq])
                           << (RuleHeadSet << (Group << _(Head) << _[Tail])))
@@ -282,7 +282,7 @@ namespace rego
            << (RuleRefToken[RefHead] * RuleRefToken++[RefArgSeq] * T(Contains) *
                ExprToken[Head] * ExprToken++[Tail])) >>
         [](Match& _) {
-          return Rule << JSONFalse
+          return Rule << False
                       << (RuleHead
                           << (RuleRef << _(RefHead) << _[RefArgSeq])
                           << (RuleHeadSet << (Group << _(Head) << _[Tail])))
diff --git a/src/passes/skips.cc b/src/passes/skips.cc
index 57ff1d99..9c6f53fa 100644
--- a/src/passes/skips.cc
+++ b/src/passes/skips.cc
@@ -107,8 +107,7 @@ namespace rego
         In(DataModule) *
             (T(DataRule) << (T(Var)[Var] * T(DataTerm)[DataTerm])) >>
           [](Match& _) {
-            return RuleComp << _(Var) << Empty << _(DataTerm)
-                            << (JSONInt ^ "0");
+            return RuleComp << _(Var) << Empty << _(DataTerm) << (Int ^ "0");
           },
       }};
 
diff --git a/src/passes/structure.cc b/src/passes/structure.cc
index 787c9fe6..b05a9fbe 100644
--- a/src/passes/structure.cc
+++ b/src/passes/structure.cc
@@ -280,8 +280,7 @@ namespace rego
       In(RuleArgs) * (T(Group) << TermToken[Val]) >>
         [](Match& _) { return Term << _(Val); },
 
-      In(RuleArgs) *
-          (T(Group) << (T(Subtract) * (T(JSONInt) / T(JSONFloat))[Val])) >>
+      In(RuleArgs) * (T(Group) << (T(Subtract) * (T(Int) / T(Float))[Val])) >>
         [](Match& _) { return Term << (Scalar << Resolver::negate(_(Val))); },
 
       In(ExprEvery) * (T(Group) << (T(IsIn) * ExprToken++[Expr] * End)) >>
diff --git a/src/passes/symbols.cc b/src/passes/symbols.cc
index 71908b10..a4b62329 100644
--- a/src/passes/symbols.cc
+++ b/src/passes/symbols.cc
@@ -62,7 +62,7 @@ namespace rego
 
       In(Policy) *
           (T(Rule)
-           << (T(JSONFalse) *
+           << (T(False) *
                (T(RuleHead)
                 << ((T(RuleRef) << T(Var)[Id]) *
                     (T(RuleHeadComp) << (T(AssignOperator) * T(Expr)[Expr])))) *
@@ -71,7 +71,7 @@ namespace rego
           Node elseseq = _(ElseSeq);
           if (elseseq->size() == 0)
           {
-            return RuleComp << _(Id) << _(Body) << _(Expr) << (JSONInt ^ "0");
+            return RuleComp << _(Id) << _(Body) << _(Expr) << (Int ^ "0");
           }
 
           // we need to create sub-rules for each possibility
@@ -80,14 +80,14 @@ namespace rego
           Node seq = NodeDef::create(Seq);
           seq
             << (RuleComp << (Var ^ subrule) << _(Body) << _(Expr)
-                         << (JSONInt ^ "0"));
+                         << (Int ^ "0"));
           for (std::size_t i = 0; i < elseseq->size(); ++i)
           {
             Node expr = elseseq->at(i) / Val;
             Node body = elseseq->at(i) / Body;
             seq
               << (RuleComp << (Var ^ subrule) << body << expr
-                           << (JSONInt ^ std::to_string(i + 1)));
+                           << (Int ^ std::to_string(i + 1)));
           }
 
           Location value = _.fresh({"value"});
@@ -97,12 +97,12 @@ namespace rego
                              << (Literal
                                  << (Expr << (RefTerm << (Var ^ value)) << Unify
                                           << (RefTerm << (Var ^ subrule)))))
-                         << (JSONInt ^ "0"));
+                         << (Int ^ "0"));
         },
 
       In(Policy) *
           (T(Rule)
-           << (T(JSONTrue) *
+           << (T(True) *
                (T(RuleHead)
                 << ((T(RuleRef) << T(Var)[Id]) *
                     (T(RuleHeadComp) << (T(AssignOperator) * T(Expr)[Expr])))) *
@@ -110,12 +110,12 @@ namespace rego
         [](Match& _) {
           std::size_t rank = std::numeric_limits<std::uint16_t>::max();
           return RuleComp << _(Id) << Empty << _(Expr)
-                          << (JSONInt ^ std::to_string(rank));
+                          << (Int ^ std::to_string(rank));
         },
 
       In(Policy) *
           (T(Rule)
-           << (T(JSONFalse) *
+           << (T(False) *
                (T(RuleHead)
                 << ((T(RuleRef) << T(Var)[Id]) *
                     (T(RuleHeadFunc)
@@ -127,7 +127,7 @@ namespace rego
           if (elseseq->size() == 0)
           {
             return RuleFunc << _(Id) << _(RuleArgs) << _(Body) << _(Expr)
-                            << (JSONInt ^ "0");
+                            << (Int ^ "0");
           }
 
           // we need to create sub-rules for each possibility
@@ -136,14 +136,14 @@ namespace rego
           Node seq = NodeDef::create(Seq);
           seq
             << (RuleFunc << (Var ^ subrule) << _(RuleArgs) << _(Body) << _(Expr)
-                         << (JSONInt ^ "0"));
+                         << (Int ^ "0"));
           for (std::size_t i = 0; i < elseseq->size(); ++i)
           {
             Node expr = elseseq->at(i) / Val;
             Node body = elseseq->at(i) / Body;
             seq
               << (RuleFunc << (Var ^ subrule) << _(RuleArgs)->clone() << body
-                           << expr << (JSONInt ^ std::to_string(i + 1)));
+                           << expr << (Int ^ std::to_string(i + 1)));
           }
 
           Location value = _.fresh({"value"});
@@ -168,12 +168,12 @@ namespace rego
                                           << (ExprCall
                                               << (RuleRef << (Var ^ subrule))
                                               << argseq))))
-                         << (JSONInt ^ "0"));
+                         << (Int ^ "0"));
         },
 
       In(Policy) *
           (T(Rule)
-           << (T(JSONTrue) *
+           << (T(True) *
                (T(RuleHead)
                 << ((T(RuleRef) << T(Var)[Id]) *
                     (T(RuleHeadFunc)
@@ -183,12 +183,12 @@ namespace rego
         [](Match& _) {
           std::size_t rank = std::numeric_limits<std::uint16_t>::max();
           return RuleFunc << _(Id) << _(RuleArgs) << Empty << _(Expr)
-                          << (JSONInt ^ std::to_string(rank));
+                          << (Int ^ std::to_string(rank));
         },
 
       In(Policy) *
           (T(Rule)
-           << (T(JSONFalse) *
+           << (T(False) *
                (T(RuleHead)
                 << ((T(RuleRef) << T(Var)[Id]) *
                     (T(RuleHeadSet) << T(Expr)[Expr]))) *
@@ -197,7 +197,7 @@ namespace rego
 
       In(Policy) *
           (T(Rule)
-           << (T(JSONFalse) *
+           << (T(False) *
                (T(RuleHead)
                 << ((T(RuleRef) << T(Var)[Id]) *
                     (T(RuleHeadObj)
@@ -213,7 +213,7 @@ namespace rego
       In(Expr) * (T(Term) << (T(Ref) / T(Var))[Val]) >>
         [](Match& _) { return RefTerm << _(Val); },
 
-      In(Expr) * (T(Term) << (T(Scalar) << (T(JSONInt) / T(JSONFloat))[Val])) >>
+      In(Expr) * (T(Term) << (T(Scalar) << (T(Int) / T(Float))[Val])) >>
         [](Match& _) { return NumTerm << _(Val); },
 
       In(Expr) * (T(Term) << (T(Set) / T(SetCompr))[Set]) >>
@@ -245,11 +245,11 @@ namespace rego
                          << (Expr
                              << _(Item) << Unify
                              << (RefTerm
-                                 << (Ref << (RefHead << (Var ^ item))
-                                         << (RefArgSeq
-                                             << (RefArgBrack
-                                                 << (Scalar
-                                                     << (JSONInt ^ "1"))))))));
+                                 << (Ref
+                                     << (RefHead << (Var ^ item))
+                                     << (RefArgSeq
+                                         << (RefArgBrack
+                                             << (Scalar << (Int ^ "1"))))))));
         },
 
       In(UnifyBody) *
@@ -265,20 +265,20 @@ namespace rego
                          << (Expr
                              << _(Idx) << Unify
                              << (RefTerm
-                                 << (Ref << (RefHead << (Var ^ item))
-                                         << (RefArgSeq
-                                             << (RefArgBrack
-                                                 << (Scalar
-                                                     << (JSONInt ^ "0"))))))))
+                                 << (Ref
+                                     << (RefHead << (Var ^ item))
+                                     << (RefArgSeq
+                                         << (RefArgBrack
+                                             << (Scalar << (Int ^ "0"))))))))
                      << (Literal
                          << (Expr
                              << _(Item) << Unify
                              << (RefTerm
-                                 << (Ref << (RefHead << (Var ^ item))
-                                         << (RefArgSeq
-                                             << (RefArgBrack
-                                                 << (Scalar
-                                                     << (JSONInt ^ "1"))))))));
+                                 << (Ref
+                                     << (RefHead << (Var ^ item))
+                                     << (RefArgSeq
+                                         << (RefArgBrack
+                                             << (Scalar << (Int ^ "1"))))))));
         },
 
       In(UnifyBody, LiteralWith) *
@@ -379,11 +379,10 @@ namespace rego
             << (Literal
                 << (Expr << (RefTerm << _(Val)->clone()) << Unify
                          << (RefTerm
-                             << (Ref
-                                 << (RefHead << (Var ^ item))
-                                 << (RefArgSeq
-                                     << (RefArgBrack
-                                         << (Scalar << (JSONInt ^ "1"))))))))
+                             << (Ref << (RefHead << (Var ^ item))
+                                     << (RefArgSeq
+                                         << (RefArgBrack
+                                             << (Scalar << (Int ^ "1"))))))))
             << *_[UnifyBody];
 
           return Seq << (Lift << UnifyBody
@@ -421,19 +420,17 @@ namespace rego
             << (Literal
                 << (Expr << (RefTerm << _(Idx)->clone()) << Unify
                          << (RefTerm
-                             << (Ref
-                                 << (RefHead << (Var ^ item))
-                                 << (RefArgSeq
-                                     << (RefArgBrack
-                                         << (Scalar << (JSONInt ^ "0"))))))))
+                             << (Ref << (RefHead << (Var ^ item))
+                                     << (RefArgSeq
+                                         << (RefArgBrack
+                                             << (Scalar << (Int ^ "0"))))))))
             << (Literal
                 << (Expr << (RefTerm << _(Val)->clone()) << Unify
                          << (RefTerm
-                             << (Ref
-                                 << (RefHead << (Var ^ item))
-                                 << (RefArgSeq
-                                     << (RefArgBrack
-                                         << (Scalar << (JSONInt ^ "1"))))))))
+                             << (Ref << (RefHead << (Var ^ item))
+                                     << (RefArgSeq
+                                         << (RefArgBrack
+                                             << (Scalar << (Int ^ "1"))))))))
             << *_[UnifyBody];
 
           return Seq << (Lift << UnifyBody
diff --git a/src/passes/unify.cc b/src/passes/unify.cc
index 0db157b6..095b3f0e 100644
--- a/src/passes/unify.cc
+++ b/src/passes/unify.cc
@@ -9,7 +9,7 @@ namespace rego
       dir::bottomup | dir::once,
       {
         In(Input) * T(Term) >>
-          ([](Match&) -> Node { return Term << (Scalar << JSONNull); }),
+          ([](Match&) -> Node { return Term << (Scalar << Null); }),
         In(Data) * T(DataModule) >> ([](Match&) -> Node { return DataModule; }),
         In(Rego) * T(SkipSeq) >> ([](Match&) -> Node { return SkipSeq; }),
         In(Query, Array, Set, ObjectItem) *
diff --git a/src/lang.cc b/src/rego.cc
similarity index 97%
rename from src/lang.cc
rename to src/rego.cc
index d71e8439..a31bd165 100644
--- a/src/lang.cc
+++ b/src/rego.cc
@@ -2,7 +2,7 @@
 
 namespace rego
 {
-  bool Logger::enabled = false;
+  LogLevel Logger::maximum_level = LogLevel::None;
   std::string Logger::indent = "";
 
   std::vector<PassCheck> passes(const BuiltIns& builtins)
@@ -109,8 +109,8 @@ namespace rego
     return d;
   }
 
-  void set_logging_enabled(bool enabled)
+  void set_log_level(LogLevel level)
   {
-    Logger::enabled = enabled;
+    Logger::maximum_level = level;
   }
 }
\ No newline at end of file
diff --git a/src/rego_c.cc b/src/rego_c.cc
index 6f5c6ebe..ca916146 100644
--- a/src/rego_c.cc
+++ b/src/rego_c.cc
@@ -21,9 +21,34 @@ extern "C"
     return reinterpret_cast<rego::Interpreter*>(rego)->m_c_error.c_str();
   }
 
-  void regoSetLoggingEnabled(regoBoolean enabled)
+  void regoSetLogLevel(regoEnum level)
   {
-    rego::set_logging_enabled(enabled);
+    switch (level)
+    {
+      case REGO_LOG_LEVEL_NONE:
+        rego::set_log_level(rego::LogLevel::None);
+        break;
+
+      case REGO_LOG_LEVEL_ERROR:
+        rego::set_log_level(rego::LogLevel::Error);
+        break;
+
+      case REGO_LOG_LEVEL_WARN:
+        rego::set_log_level(rego::LogLevel::Warn);
+        break;
+
+      case REGO_LOG_LEVEL_INFO:
+        rego::set_log_level(rego::LogLevel::Info);
+        break;
+
+      case REGO_LOG_LEVEL_DEBUG:
+        rego::set_log_level(rego::LogLevel::Debug);
+        break;
+
+      case REGO_LOG_LEVEL_TRACE:
+        rego::set_log_level(rego::LogLevel::Trace);
+        break;
+    }
   }
 
   regoInterpreter* regoNew()
@@ -279,12 +304,12 @@ extern "C"
       return REGO_NODE_OBJECT_ITEM;
     }
 
-    if (node->type() == rego::JSONInt)
+    if (node->type() == rego::Int)
     {
       return REGO_NODE_INT;
     }
 
-    if (node->type() == rego::JSONFloat)
+    if (node->type() == rego::Float)
     {
       return REGO_NODE_FLOAT;
     }
@@ -294,17 +319,17 @@ extern "C"
       return REGO_NODE_STRING;
     }
 
-    if (node->type() == rego::JSONTrue)
+    if (node->type() == rego::True)
     {
       return REGO_NODE_TRUE;
     }
 
-    if (node->type() == rego::JSONFalse)
+    if (node->type() == rego::False)
     {
       return REGO_NODE_FALSE;
     }
 
-    if (node->type() == rego::JSONNull)
+    if (node->type() == rego::Null)
     {
       return REGO_NODE_NULL;
     }
diff --git a/src/resolver.cc b/src/resolver.cc
index 006f12df..c1f7df81 100644
--- a/src/resolver.cc
+++ b/src/resolver.cc
@@ -65,7 +65,7 @@ namespace
       return err(op, "unsupported math operation");
     }
 
-    return JSONInt ^ value.loc();
+    return Int ^ value.loc();
   }
 
   Node do_arith(const Node& op, double lhs, double rhs)
@@ -104,7 +104,7 @@ namespace
     std::ostringstream oss;
     oss << std::setprecision(std::numeric_limits<double>::max_digits10 - 1)
         << std::noshowpoint << value;
-    return JSONFloat ^ oss.str();
+    return Float ^ oss.str();
   }
 
   Node do_bool(const Node& op, BigInt lhs, BigInt rhs)
@@ -141,11 +141,11 @@ namespace
 
     if (value)
     {
-      return JSONTrue ^ "true";
+      return True ^ "true";
     }
     else
     {
-      return JSONFalse ^ "false";
+      return False ^ "false";
     }
   }
 
@@ -183,11 +183,11 @@ namespace
 
     if (value)
     {
-      return JSONTrue ^ "true";
+      return True ^ "true";
     }
     else
     {
-      return JSONFalse ^ "false";
+      return False ^ "false";
     }
   }
 
@@ -225,11 +225,11 @@ namespace
 
     if (value)
     {
-      return JSONTrue ^ "true";
+      return True ^ "true";
     }
     else
     {
-      return JSONFalse ^ "false";
+      return False ^ "false";
     }
   }
 }
@@ -238,7 +238,7 @@ namespace rego
 {
   Node Resolver::scalar(BigInt value)
   {
-    return JSONInt ^ value.loc();
+    return Int ^ value.loc();
   }
 
   Node Resolver::scalar(double value)
@@ -246,12 +246,12 @@ namespace rego
     std::ostringstream oss;
     oss << std::setprecision(std::numeric_limits<double>::max_digits10 - 1)
         << std::noshowpoint << value;
-    return JSONFloat ^ oss.str();
+    return Float ^ oss.str();
   }
 
   Node Resolver::scalar()
   {
-    return JSONNull ^ "null";
+    return Null ^ "null";
   }
 
   Node Resolver::term(BigInt value)
@@ -298,26 +298,26 @@ namespace rego
   {
     if (value)
     {
-      return JSONTrue ^ "true";
+      return True ^ "true";
     }
     else
     {
-      return JSONFalse ^ "false";
+      return False ^ "false";
     }
   }
 
   Node Resolver::negate(const Node& node)
   {
-    if (node->type() == JSONInt)
+    if (node->type() == Int)
     {
       BigInt value = get_int(node);
-      return JSONInt ^ value.negate().loc();
+      return Int ^ value.negate().loc();
     }
-    else if (node->type() == JSONFloat)
+    else if (node->type() == Float)
     {
       double value = get_double(node);
       value *= -1.0;
-      return JSONFloat ^ std::to_string(value);
+      return Float ^ std::to_string(value);
     }
     else
     {
@@ -329,7 +329,7 @@ namespace rego
   {
     if (lhs->type() == Undefined || rhs->type() == Undefined)
     {
-      return JSONFalse ^ "false";
+      return False ^ "false";
     }
 
     if (lhs->type() == Error)
@@ -342,15 +342,15 @@ namespace rego
       return rhs;
     }
 
-    auto maybe_lhs_number = unwrap(lhs, {JSONInt, JSONFloat});
-    auto maybe_rhs_number = unwrap(rhs, {JSONInt, JSONFloat});
+    auto maybe_lhs_number = unwrap(lhs, {Int, Float});
+    auto maybe_rhs_number = unwrap(rhs, {Int, Float});
 
     if (maybe_lhs_number.success && maybe_rhs_number.success)
     {
       Node lhs_number = maybe_lhs_number.node;
       Node rhs_number = maybe_rhs_number.node;
       if (
-        lhs_number->type() == JSONInt && rhs_number->type() == JSONInt &&
+        lhs_number->type() == Int && rhs_number->type() == Int &&
         op->type() != Divide)
       {
         return do_arith(op, get_int(lhs_number), get_int(rhs_number));
@@ -414,7 +414,7 @@ namespace rego
   {
     if (lhs->type() == Undefined || rhs->type() == Undefined)
     {
-      return JSONFalse ^ "false";
+      return False ^ "false";
     }
 
     if (lhs->type() == Error)
@@ -427,14 +427,14 @@ namespace rego
       return rhs;
     }
 
-    auto maybe_lhs_number = unwrap(lhs, {JSONInt, JSONFloat});
-    auto maybe_rhs_number = unwrap(rhs, {JSONInt, JSONFloat});
+    auto maybe_lhs_number = unwrap(lhs, {Int, Float});
+    auto maybe_rhs_number = unwrap(rhs, {Int, Float});
 
     if (maybe_lhs_number.success && maybe_rhs_number.success)
     {
       Node lhs_number = maybe_lhs_number.node;
       Node rhs_number = maybe_rhs_number.node;
-      if (lhs_number->type() == JSONInt && rhs_number->type() == JSONInt)
+      if (lhs_number->type() == Int && rhs_number->type() == Int)
       {
         return do_bool(op, get_int(lhs_number), get_int(rhs_number));
       }
@@ -470,7 +470,7 @@ namespace rego
         index = index->front();
       }
 
-      if (index->type() == JSONInt)
+      if (index->type() == Int)
       {
         auto i = get_int(index).to_size();
         if (i < container->size())
@@ -569,9 +569,9 @@ namespace rego
     }
 
     if (
-      value->type() == JSONInt || value->type() == JSONFloat ||
-      value->type() == JSONString || value->type() == JSONTrue ||
-      value->type() == JSONFalse || value->type() == JSONNull)
+      value->type() == Int || value->type() == Float ||
+      value->type() == JSONString || value->type() == True ||
+      value->type() == False || value->type() == Null)
     {
       return Term << (Scalar << value);
     }
@@ -638,7 +638,7 @@ namespace rego
 
   Node Resolver::unary(const Node& value)
   {
-    auto maybe_number = unwrap(value, {JSONInt, JSONFloat});
+    auto maybe_number = unwrap(value, {Int, Float});
     if (maybe_number.success)
     {
       return negate(maybe_number.node);
@@ -1233,7 +1233,7 @@ namespace rego
     }
     else
     {
-      return JSONFalse ^ "false";
+      return False ^ "false";
     }
 
     std::string index_str = to_json(index);
@@ -1241,11 +1241,11 @@ namespace rego
     {
       if (i == index_str)
       {
-        return JSONTrue ^ "true";
+        return True ^ "true";
       }
     }
 
-    return JSONFalse ^ "false";
+    return False ^ "false";
   }
 
   Node Resolver::membership(const Node& item, const Node& itemseq)
@@ -1267,15 +1267,15 @@ namespace rego
     }
     else
     {
-      return JSONFalse ^ "false";
+      return False ^ "false";
     }
 
     if (indices.size() > 0)
     {
-      return JSONTrue ^ "True";
+      return True ^ "True";
     }
 
-    return JSONFalse ^ "false";
+    return False ^ "false";
   }
 
   std::vector<std::string> Resolver::array_find(
diff --git a/src/unifier.cc b/src/unifier.cc
index 0647955b..49e911f8 100644
--- a/src/unifier.cc
+++ b/src/unifier.cc
@@ -291,7 +291,7 @@ namespace rego
         {
           if (m_negate && var.is_unify())
           {
-            var.unify({ValueDef::create(JSONTrue ^ "true")});
+            var.unify({ValueDef::create(True ^ "true")});
             LOG("> result: ", var);
           }
           else
@@ -318,7 +318,7 @@ namespace rego
               {
                 value->mark_as_valid();
               }
-              var.unify({ValueDef::create(JSONTrue ^ "true")});
+              var.unify({ValueDef::create(True ^ "true")});
               LOG("> result: ", var);
             }
             else
@@ -406,7 +406,7 @@ namespace rego
             if (node->size() == 0)
             {
               LOG("> ", var.name().view(), ": Empty TermSet => false");
-              return JSONFalse ^ "false";
+              return False ^ "false";
             }
             Node maybe_term = Resolver::reduce_termset(node);
             if (maybe_term->type() == Term)
@@ -414,7 +414,7 @@ namespace rego
               if (result->type() == Undefined)
               {
                 LOG("> ", var.name().view(), ": TermSet => true");
-                return JSONTrue ^ "true";
+                return True ^ "true";
               }
             }
             else
@@ -429,28 +429,28 @@ namespace rego
           else if (node->size() > 0 && result->type() == Undefined)
           {
             LOG("> ", var.name().view(), ": TermSet => true");
-            return JSONTrue ^ "true";
+            return True ^ "true";
           }
           else if (node->size() == 0 && var.is_user_var())
           {
             LOG("> ", var.name().view(), ": Empty TermSet => false");
-            return JSONFalse ^ "false";
+            return False ^ "false";
           }
         }
         else if (var.is_unify() && is_falsy(node))
         {
           LOG("> ", var.name().view(), ": false => false");
-          return JSONFalse ^ "false";
+          return False ^ "false";
         }
         else if (node->type() == Term && result->type() == Undefined)
         {
           LOG("> ", var.name().view(), ": Term => true");
-          return JSONTrue ^ "true";
+          return True ^ "true";
         }
         else if (var.is_user_var() && is_undefined(node))
         {
           LOG("> ", var.name().view(), ": undefined => false");
-          return JSONFalse ^ "false";
+          return False ^ "false";
         }
 
         LOG("> ", var.name().view(), ": ", result->location().view());
@@ -1043,11 +1043,11 @@ namespace rego
       Node term = args[0]->to_term();
       if (is_truthy(term))
       {
-        return ValueDef::create(var, JSONFalse ^ "false", sources);
+        return ValueDef::create(var, False ^ "false", sources);
       }
       else
       {
-        return ValueDef::create(var, JSONTrue ^ "true", sources);
+        return ValueDef::create(var, True ^ "true", sources);
       }
     }
 
@@ -1171,7 +1171,7 @@ namespace rego
       {
         for (std::size_t i = 0; i < container->size(); ++i)
         {
-          Node index = Scalar << (JSONInt ^ std::to_string(i));
+          Node index = Scalar << (Int ^ std::to_string(i));
           Node tuple = Term << (Array << index << container->at(i));
           items.push_back(ValueDef::create(var, tuple));
         }
@@ -1598,7 +1598,7 @@ namespace rego
       Node body_result;
       if (rulebody->type() == Empty)
       {
-        body_result = JSONTrue;
+        body_result = True;
       }
       else
       {
@@ -1619,7 +1619,7 @@ namespace rego
         return body_result;
       }
 
-      if (body_result->type() == JSONTrue)
+      if (body_result->type() == True)
       {
         if (value->type() == UnifyBody)
         {
@@ -1656,7 +1656,7 @@ namespace rego
         continue;
       }
 
-      if (body_result->type() == JSONTrue)
+      if (body_result->type() == True)
       {
         if (result == nullptr)
         {
@@ -1718,7 +1718,7 @@ namespace rego
 
     if (rulebody->type() == Empty)
     {
-      body_result = JSONTrue;
+      body_result = True;
     }
     else
     {
@@ -1739,7 +1739,7 @@ namespace rego
       return std::make_pair(index, body_result);
     }
 
-    if (body_result->type() == JSONFalse || body_result->type() == Undefined)
+    if (body_result->type() == False || body_result->type() == Undefined)
     {
       LOG("No value");
       return std::nullopt;
@@ -1794,7 +1794,7 @@ namespace rego
       Node body_result;
       if (rulebody->type() == Empty)
       {
-        body_result = JSONTrue;
+        body_result = True;
       }
       else
       {
@@ -1815,7 +1815,7 @@ namespace rego
         return body_result;
       }
 
-      if (body_result->type() == JSONTrue)
+      if (body_result->type() == True)
       {
         if (value->type() == UnifyBody)
         {
@@ -1844,7 +1844,7 @@ namespace rego
         }
       }
 
-      if (body_result->type() == JSONTrue && value->type() == Term)
+      if (body_result->type() == True && value->type() == Term)
       {
         Node set = value->front();
         argseq->insert(argseq->end(), set->begin(), set->end());
@@ -1889,7 +1889,7 @@ namespace rego
       Node body_result;
       if (rulebody->type() == Empty)
       {
-        body_result = JSONTrue;
+        body_result = True;
       }
       else
       {
@@ -1910,7 +1910,7 @@ namespace rego
         return body_result;
       }
 
-      if (body_result->type() == JSONTrue)
+      if (body_result->type() == True)
       {
         if (value->type() == UnifyBody)
         {
@@ -1939,7 +1939,7 @@ namespace rego
         }
       }
 
-      if (body_result->type() == JSONTrue && value->type() == Term)
+      if (body_result->type() == True && value->type() == Term)
       {
         Node obj = value->front();
         for (Node item : *obj)
diff --git a/src/value.cc b/src/value.cc
index 6672aa31..1f1e06b2 100644
--- a/src/value.cc
+++ b/src/value.cc
@@ -4,8 +4,7 @@ namespace
 {
   using namespace rego;
 
-  std::set<Token> scalar_tokens = {
-    JSONInt, JSONFloat, JSONString, JSONTrue, JSONFalse, JSONNull};
+  std::set<Token> scalar_tokens = {Int, Float, JSONString, True, False, Null};
   std::set<Token> term_tokens = {Scalar, Array, Object, Set, Undefined};
 }
 
diff --git a/src/variable.cc b/src/variable.cc
index 94caa116..61faa75c 100644
--- a/src/variable.cc
+++ b/src/variable.cc
@@ -176,7 +176,7 @@ namespace rego
   {
     if (!m_unify && !m_user_var)
     {
-      return JSONTrue ^ "true";
+      return True ^ "true";
     }
 
     Node term = to_term();
diff --git a/tools/main.cc b/tools/main.cc
index 46b076fa..b10e63f3 100644
--- a/tools/main.cc
+++ b/tools/main.cc
@@ -26,8 +26,8 @@ int main(int argc, char** argv)
   std::filesystem::path output;
   app.add_option("-a,--ast", output, "Output the AST");
 
-  bool enable_logging{false};
-  app.add_flag("-l,--logging", enable_logging, "Enable logging");
+  rego::LogLevel loglevel{rego::LogLevel::None};
+  app.add_option("-l,--loglevel", loglevel, "Enable logging");
 
   try
   {
@@ -38,10 +38,9 @@ int main(int argc, char** argv)
     return app.exit(e);
   }
 
-  rego::set_logging_enabled(enable_logging);
+  rego::set_log_level(loglevel);
 
   auto interpreter = rego::Interpreter();
-  interpreter.executable(argv[0]);
   interpreter.well_formed_checks_enabled(wf_checks);
 
   if (!input_path.empty())
diff --git a/wrappers/rust/regorust/Cargo.toml b/wrappers/rust/regorust/Cargo.toml
index 6ff76933..d8658838 100644
--- a/wrappers/rust/regorust/Cargo.toml
+++ b/wrappers/rust/regorust/Cargo.toml
@@ -1,11 +1,11 @@
 [package]
 name = "regorust"
-version = "0.3.4"
+version = "0.3.5"
 edition = "2021"
 description = "Rust bindings for the rego-cpp Rego compiler and interpreter"
 license-file = "LICENSE"
 readme = "README.md"
-homepage = "https://github.com/microsoft/rego-cpp"
+homepage = "https://microsoft.github.io/rego-cpp/"
 repository = "https://github.com/microsoft/rego-cpp"
 
 [dependencies]
diff --git a/wrappers/rust/regorust/README.md b/wrappers/rust/regorust/README.md
index 68679001..cdb0b63f 100644
--- a/wrappers/rust/regorust/README.md
+++ b/wrappers/rust/regorust/README.md
@@ -12,3 +12,131 @@ by Microsoft. You can learn more about that project
 wrapper we try to provide idiomatic Rust interfaces to the Rego query engine.
 We hope the project is of use to those wishing to leverage the power of Rego
 within a Rust context.
+
+> **Warning**
+> While this project has progressed to the point that we support full Rego language
+> (see [Language Support](#language-support) below) we do not support all built-ins.
+> That said, we have verified compliance with the OPA Rego test suite. Even so, it
+> should still be considered experimental software and used with discretion.
+
+## Language Support
+
+At present we support v0.55.0 of Rego as defined by OPA, with the following grammar:
+
+```ebnf
+module          = package { import } policy
+package         = "package" ref
+import          = "import" ref [ "as" var ]
+policy          = { rule }
+rule            = [ "default" ] rule-head { rule-body }
+rule-head       = ( ref | var ) ( rule-head-set | rule-head-obj | rule-head-func | rule-head-comp )
+rule-head-comp  = [ assign-operator term ] [ "if" ]
+rule-head-obj   = "[" term "]" [ assign-operator term ] [ "if" ]
+rule-head-func  = "(" rule-args ")" [ assign-operator term ] [ "if" ]
+rule-head-set   = "contains" term [ "if" ] | "[" term "]"
+rule-args       = term { "," term }
+rule-body       = [ "else" [ assign-operator term ] [ "if" ] ] ( "{" query "}" ) | literal
+query           = literal { ( ";" | ( [CR] LF ) ) literal }
+literal         = ( some-decl | expr | "not" expr ) { with-modifier }
+with-modifier   = "with" term "as" term
+some-decl       = "some" term { "," term } { "in" expr }
+expr            = term | expr-call | expr-infix | expr-every | expr-parens | unary-expr
+expr-call       = var [ "." var ] "(" [ expr { "," expr } ] ")"
+expr-infix      = expr infix-operator expr
+expr-every      = "every" var { "," var } "in" ( term | expr-call | expr-infix ) "{" query "}"
+expr-parens     = "(" expr ")"
+unary-expr      = "-" expr
+membership      = term [ "," term ] "in" term
+term            = ref | var | scalar | array | object | set | membership | array-compr | object-compr | set-compr
+array-compr     = "[" term "|" query "]"
+set-compr       = "{" term "|" query "}"
+object-compr    = "{" object-item "|" query "}"
+infix-operator  = assign-operator | bool-operator | arith-operator | bin-operator
+bool-operator   = "==" | "!=" | "<" | ">" | ">=" | "<="
+arith-operator  = "+" | "-" | "*" | "/"
+bin-operator    = "&" | "|"
+assign-operator = ":=" | "="
+ref             = ( var | array | object | set | array-compr | object-compr | set-compr | expr-call ) { ref-arg }
+ref-arg         = ref-arg-dot | ref-arg-brack
+ref-arg-brack   = "[" ( scalar | var | array | object | set | "_" ) "]"
+ref-arg-dot     = "." var
+var             = ( ALPHA | "_" ) { ALPHA | DIGIT | "_" }
+scalar          = string | NUMBER | TRUE | FALSE | NULL
+string          = STRING | raw-string
+raw-string      = "`" { CHAR-"`" } "`"
+array           = "[" term { "," term } "]"
+object          = "{" object-item { "," object-item } "}"
+object-item     = ( scalar | ref | var ) ":" term
+set             = empty-set | non-empty-set
+non-empty-set   = "{" term { "," term } "}"
+empty-set       = "set(" ")"
+```
+
+Definitions:
+```
+[]     optional (zero or one instances)
+{}     repetition (zero or more instances)
+|      alternation (one of the instances)
+()     grouping (order of expansion)
+STRING JSON string
+NUMBER JSON number
+TRUE   JSON true
+FALSE  JSON false
+NULL   JSON null
+CHAR   Unicode character
+ALPHA  ASCII characters A-Z and a-z
+DIGIT  ASCII characters 0-9
+CR     Carriage Return
+LF     Line Feed
+```
+
+### Builtins
+
+At the moment only support a few builtins, but are actively working on adding
+all the standard builtins. The following builtins are currently supported:
+
+- `aggregates`
+- `arrays`
+- `bits`
+- `casts`
+- `numbers`
+- `objects`
+- `regex`
+- `semver`
+- `sets`
+- `strings`
+- `types`
+- `units`
+- miscellaneous
+    * `base64_encode`
+    * `base64_decode`
+    * `json.marshal`
+    * `opa.runtime`
+    * `print`
+    * `time.now_ns`
+
+### Compatibility with the OPA Rego Go implementation
+
+Our goal is to achieve and maintain full compatibility with the reference Go
+implementation. We have developed a test driver which runs the same tests
+and validates that we produce the same outputs. At this stage we pass all
+the non-builtin specific test suites, which we clone from the
+[OPA repository](https://github.com/open-policy-agent/opa/tree/main/test/cases/testdata).
+To build with the OPA tests available for testing, use one of the following presets:
+- `release-clang-opa`
+- `release-opa`
+
+At present, we are **NOT** passing the following test suites in full:
+- `base64*`
+- `crypto*`
+- `glob*`
+- `graphql`
+- `invalidkeyerror`
+- `json*`
+- `jwt*`
+- `net*`
+- `planner-ir`
+- `providers-aws`
+- `reachable`
+- `urlbuiltins`
+- `walkbuiltin`
diff --git a/wrappers/rust/regorust/build.rs b/wrappers/rust/regorust/build.rs
index f7c44fa9..7a05b184 100644
--- a/wrappers/rust/regorust/build.rs
+++ b/wrappers/rust/regorust/build.rs
@@ -86,7 +86,7 @@ fn main() {
     println!("cargo:rustc-link-lib=static=rego");
     if cfg!(windows) {
         println!("cargo:rustc-link-arg=mincore.lib");
-    } else if (cfg!(target_os = "macos")) {
+    } else if cfg!(target_os = "macos") {
         println!("cargo:rustc-link-lib=c++");
     } else {
         println!("cargo:rustc-link-lib=stdc++");
diff --git a/wrappers/rust/regorust/src/lib.rs b/wrappers/rust/regorust/src/lib.rs
index f087542b..c45f925b 100644
--- a/wrappers/rust/regorust/src/lib.rs
+++ b/wrappers/rust/regorust/src/lib.rs
@@ -312,15 +312,24 @@ pub enum NodeValue {
     Null,
 }
 
-/// Sets whether verbose logging is enabled for the library
-///
-/// When enabled, the Rego library will output extensive information
-/// about its internal state to stdout. This is useful for debugging
-/// the library itself, but is not useful for debugging Rego policies.
-pub fn set_logging_enabled(enabled: bool) {
-    let c_enabled: regoBoolean = if enabled { 1 } else { 0 };
-    unsafe {
-        regoSetLoggingEnabled(c_enabled);
+pub enum LogLevel {
+    None,
+    Debug,
+    Info,
+    Warn,
+    Error,
+    Trace,
+}
+
+/// Sets the level of logging produced by the library.
+pub fn set_log_level(level: LogLevel) {
+    match level {
+        LogLevel::None => unsafe { regoSetLogLevel(REGO_LOG_LEVEL_NONE) },
+        LogLevel::Debug => unsafe { regoSetLogLevel(REGO_LOG_LEVEL_DEBUG) },
+        LogLevel::Info => unsafe { regoSetLogLevel(REGO_LOG_LEVEL_INFO) },
+        LogLevel::Warn => unsafe { regoSetLogLevel(REGO_LOG_LEVEL_WARN) },
+        LogLevel::Error => unsafe { regoSetLogLevel(REGO_LOG_LEVEL_ERROR) },
+        LogLevel::Trace => unsafe { regoSetLogLevel(REGO_LOG_LEVEL_TRACE) },
     }
 }
 


Test patch:
diff --git a/tests/main.cc b/tests/main.cc
index 03a0cdca..742237f7 100644
--- a/tests/main.cc
+++ b/tests/main.cc
@@ -65,8 +65,8 @@ int main(int argc, char** argv)
   app.add_option(
     "-a,--ast", debug_path, "Output the AST (debugging for test case parser)");
 
-  bool enable_logging{false};
-  app.add_flag("-l,--logging", enable_logging, "Enable logging");
+  rego::LogLevel loglevel{rego::LogLevel::None};
+  app.add_option("-l,--loglevel", loglevel, "Enable logging");
 
   bool wf_checks{false};
   app.add_flag("-w,--wf", wf_checks, "Enable well-formedness checks (slow)");
@@ -90,7 +90,7 @@ int main(int argc, char** argv)
     return app.exit(e);
   }
 
-  rego::set_logging_enabled(enable_logging);
+  rego::set_log_level(loglevel);
 
   std::cout << "Loading test cases:";
   TestCases all_testcases;
@@ -139,7 +139,7 @@ int main(int argc, char** argv)
       try
       {
         auto start = std::chrono::steady_clock::now();
-        auto result = testcase.run(argv[0], debug_path, wf_checks);
+        auto result = testcase.run(debug_path, wf_checks);
         auto end = std::chrono::steady_clock::now();
         const std::chrono::duration<double> elapsed = end - start;
 
diff --git a/tests/rego_test.cc b/tests/rego_test.cc
index 2fb43ee0..197fe238 100644
--- a/tests/rego_test.cc
+++ b/tests/rego_test.cc
@@ -354,19 +354,19 @@ namespace rego_test
         },
 
       In(rego::Scalar, Group) * (T(Scalar) << T(Integer)[Integer]) >>
-        [](Match& _) { return rego::JSONInt ^ _(Integer); },
+        [](Match& _) { return rego::Int ^ _(Integer); },
 
       In(rego::Scalar, Group) * (T(Scalar) << T(Float)[Float]) >>
-        [](Match& _) { return rego::JSONFloat ^ _(Float); },
+        [](Match& _) { return rego::Float ^ _(Float); },
 
       In(rego::Scalar, Group) * (T(Scalar) << T(True)[True]) >>
-        [](Match& _) { return rego::JSONTrue ^ _(True); },
+        [](Match& _) { return rego::True ^ _(True); },
 
       In(rego::Scalar, Group) * (T(Scalar) << T(False)[False]) >>
-        [](Match& _) { return rego::JSONFalse ^ _(False); },
+        [](Match& _) { return rego::False ^ _(False); },
 
       In(rego::Scalar, Group) * (T(Scalar) << T(Null)[Null]) >>
-        [](Match& _) { return rego::JSONNull ^ _(Null); },
+        [](Match& _) { return rego::Null ^ _(Null); },
 
       In(Group) * T(Mapping)[Mapping] >>
         [](Match& _) {
diff --git a/tests/rego_test.h b/tests/rego_test.h
index cd5b5145..5dfcd2df 100644
--- a/tests/rego_test.h
+++ b/tests/rego_test.h
@@ -128,8 +128,8 @@ namespace rego_test
 
   const auto inline wf_rego_term_tokens =
     rego::Scalar | rego::Object | rego::Array | rego::Set;
-  const auto inline wf_rego_scalar_tokens = rego::JSONInt | rego::JSONFloat |
-    rego::JSONString | rego::JSONTrue | rego::JSONFalse | rego::JSONNull;
+  const auto inline wf_rego_scalar_tokens = rego::Int | rego::Float |
+    rego::JSONString | rego::True | rego::False | rego::Null;
 
   // clang-format off
   inline const auto wf_pass_to_rego =
diff --git a/tests/test_case.cc b/tests/test_case.cc
index 3cd29489..1252e0ad 100644
--- a/tests/test_case.cc
+++ b/tests/test_case.cc
@@ -211,7 +211,7 @@ namespace rego_test
 
       std::string key = std::string((binding / rego::Var)->location().view());
       std::string value =
-        rego::to_json((binding / rego::Term), m_sort_bindings, false);
+        rego::to_json((binding / rego::Term), m_sort_bindings, true);
       bindings[key] = value;
     }
 
@@ -460,12 +460,9 @@ namespace rego_test
   }
 
   Result TestCase::run(
-    const std::filesystem::path& executable_path,
-    const std::filesystem::path& debug_path,
-    bool wf_checks) const
+    const std::filesystem::path& debug_path, bool wf_checks) const
   {
     rego::Interpreter interpreter;
-    interpreter.executable(executable_path);
     interpreter.well_formed_checks_enabled(wf_checks);
     interpreter.builtins().strict_errors(m_strict_error);
     if (!debug_path.empty())
diff --git a/tests/test_case.h b/tests/test_case.h
index 58e6ab13..5fd6f3d5 100644
--- a/tests/test_case.h
+++ b/tests/test_case.h
@@ -22,10 +22,7 @@ namespace rego_test
       const std::filesystem::path& path,
       const std::filesystem::path& debug_path = "");
 
-    Result run(
-      const std::filesystem::path& executable_path,
-      const std::filesystem::path& debug_path,
-      bool wf_checks) const;
+    Result run(const std::filesystem::path& debug_path, bool wf_checks) const;
 
     /** name of the test case category. */
     const std::string& category() const;