Update pure to 0.56.

Changes from previous:
----------------------
2012-11-19  Albert Graef  <Dr.Graef@t-online.de>

	* 0.56 release.

	* configure.ac, interpreter.cc/hh: LLVM 3.2 compatibility.

2012-11-13  Albert Graef  <Dr.Graef@t-online.de>

	* runtime.cc (pure_str): Alternative str() implementation which
	returns a Pure string instead of a raw C string. We use this in
	primitives.pure now to prevent the memory leaks resulting from
	calling str() directly from Pure.

	* util.cc (my_strdup, my_strfree): strdup/free replacements to
	reduce the number of temporary string allocations. This is still
	experimental.

	* interpreter.cc (compile_interface): Get rid of bogus warnings
	for abstract (unimplemented) interface types.
	(finalize_interface_rules): Fix detection of empty interfaces.
	This fixes issue #95.

	* lib/prelude.pure, lib/matrices.pure: Fixes to all, any, unzip
	(cf. issue #92 and #93). Also, smatrix accepts a dimension
	argument now like the other matrix construction functions
	(issue #96).

	* lib/primitives.pure: Improved simplifications of partially
	evaluated logical connectives. E.g., both 1&&x and x&&1 give x
	now.

2012-11-06  Albert Graef  <Dr.Graef@t-online.de>

	* texmacs: Overhaul of TeXmacs plugin.

2012-10-19  Albert Graef  <Dr.Graef@t-online.de>

	* runtime.cc (reduce): Fixed a memory leak and resolved a rather
	obscure segfault due to global closures becoming invalidated by a
	recent recompile.

2012-10-16  Albert Graef  <Dr.Graef@t-online.de>

	* lexer.ll: TeXmacs completion support.

2012-10-12  Albert Graef  <Dr.Graef@t-online.de>

	* pure.cc, lexer.ll, runtime.cc: Improved readline support: Add
	secondary command input, so that the debugger has its own command
	history.

2012-10-08  Albert Graef  <Dr.Graef@t-online.de>

	* lib/prelude.pure (n..m): Bugfix: For consistency with the
	n1:n2..m case, do a quick check that m-n yields a real value (this
	will fail if n and m don't belong to the same enumerated type,
	in which case we want to leave n..m as a normal form).

	* interpreter.cc (exec): Improvements in TeXmacs mode. The REPL
	now temporarily replaces __show__ with __texmacs__ in order to
	allow for custom pretty-printing of expressions in TeXmacs
	mode. (Note that simply redefining __show__ may break applications
	which rely on print representations returned by the `str`
	function.)

2012-10-04  Albert Graef  <Dr.Graef@t-online.de>

	* lib/primitives.pure: Rename break, trace to __break__, __trace__
	to prevent naming conflicts. While `break` isn't likely to occur
	in user code, `trace` is commonly used, e.g., as a matrix
	operation.

2012-10-02  Albert Graef  <Dr.Graef@t-online.de>

	* examples/texmacs: Added TeXmacs/LaTeX template contributed by
	Kurt Pagani.

2012-09-28  Albert Graef  <Dr.Graef@t-online.de>

	* interpreter.cc: Use a reasonable default for the advisory stack
	limit so that stack checks are always done by default.

2012-09-27  Albert Graef  <Dr.Graef@t-online.de>

	* examples/matrix_inversion.pure: Added matrix inversion example
	by Rob Hubbard, ported from Q to Pure by Jiri Spitz.

	* lexer.ll (docmd): Add -h (help) option to the del, trace and run
	commands.

2012-09-26  Albert Graef  <Dr.Graef@t-online.de>

	* etc/*: Add new break and trace builtins to keyword tables.

	* lib/primitives.pure: New break and trace builtins (see below).

	* runtime.cc/h: New pure_break() and pure_trace() primitives.
	These trigger debugging and tracing when called from a Pure
	program with debugging enabled.

2012-09-24  Albert Graef  <Dr.Graef@t-online.de>

	* examples/lu.pure: Example contributed by Johannes Engels.

	* interpreter.hh (interpreter), interpreter.cc (exec), lexer.ll
	(lex_input), runtime.cc (pure_debug_rule), pure.cc (main): Add
	minimal support for texmacs (http://www.texmacs.org/), per request
	by Kurt Pagani (issue #89).

	* etc/pure-mode.el.in: Add a pure-send-yank command which allows
	to send lines from the kill ring to the interpreter. This works in
	both pure-mode and pure-eval-mode. Also added a new
	pure-send-skip-prompts flag (enabled by default). This causes the
	send commands to preprocess input which looks like a session
	transcript containing both command prompts and results, by
	removing prompts and skipping non-command lines. This is
	convenient, in particular, to send samples of interpreter
	interactions from the online documentation.

2012-09-20  Albert Graef  <Dr.Graef@t-online.de>

	* lib/prelude.pure, lib/primitives.pure: Declare 'true' and
	'false' as nonfix symbols so that they can be used in patterns.
	Also add a 'bool' type along with a corresponding 'boolp'
	predicate for normalized truth values (0 and 1), and a 'bool'
	function to convert machine integers to normalized truth values.

2012-09-11  Albert Graef  <Dr.Graef@t-online.de>

	* lib/prelude.pure: Adjust the __do__ macro for generator clauses
	involving patterns (see below).

	* interpreter.cc (mklistcomp_expr, mkmatcomp_expr): Add the
	necessary magic to make comprehensions involving patterns filter
	out unmatched generator values automatically, as it is in Haskell.

2012-09-07  Albert Graef  <Dr.Graef@t-online.de>

	* lib/enum.pure: New enum.pure module which provides some
	convenience functions to facilitate the creation of enumeration
	types. Experimental.

2012-09-06  Albert Graef  <Dr.Graef@t-online.de>

	* lib/prelude.pure (..): Fix some glitches in the generic
	arithmetic sequences with step size, so that they work with
	general enumerated types.

2012-09-05  Albert Graef  <Dr.Graef@t-online.de>

	* pure.cc (main): Spiffy new logo for the sign-on message. You can
	disable this with the --plain option or by setting the PURE_PLAIN
	environment variable, if you prefer the old sign-on message.

2012-08-22  Albert Graef  <Dr.Graef@t-online.de>

	* parser.yy: Uncaught exceptions of mklistcomp_expr/mkmatcomp_expr
	in parser (fixes issue #88 reported by kp@scios.ch).

2012-08-15  Albert Graef  <Dr.Graef@t-online.de>

	* lexer.ll: Cosmetic changes to the parsing of special command
	syntax (fixes issue #84).

2012-08-14  Albert Graef  <Dr.Graef@t-online.de>

	* interpreter.cc (build_map): 'case' needs a separate FMap root
	for each rule so that the call to FMap::select() in try_rules()
	does the right thing (fixes issue #87 reported by Jim Pryor).

2012-07-17  Albert Graef  <Dr.Graef@t-online.de>

	* interpreter.cc/hh, runtime.cc, pure.cc, lexer.ll: Integrated a
	patch by Jim Pryor (with modifications) which allows the escape
	mode command prefix to be specified with the --escape option and
	the PURE_ESCAPE environment variable. Thanks Jim!

2012-07-16  Albert Graef  <Dr.Graef@t-online.de>

	* printer.cc (printx): Bugfix in pretty-printer: Type tags must be
	padded with whitespace if compile time expressions are printed
	with deBruijn annotations (-v2). Otherwise the pretty-printed code
	won't be reparsed correctly, since x/*...*/::y will be parsed as
	x ::y rather than x :: y.

	This bug affected, in particular, test/special.pure. Many of the
	other golden test logs were also updated accordingly.

2012-07-06  Albert Graef  <Dr.Graef@t-online.de>

	* lexer.ll, parser.yy, interpreter.cc/hh, symtable.cc/hh:
	Implemented namespace brackets, based on an idea by Yann Orlarey.
	This makes it much more convenient to use embedded domain-specific
	sublanguages in Pure. For instance, you may now write something
	like:

	outfix « »;
	namespace faust (« »);

	This means that the namespace 'faust' can now be accessed on the
	fly in expressions like «(a,b,c) : (sin,cos,tan)». The
	subexpression inside the namespace brackets is then parsed by
	temporarily switching to the corresponding namespace. The
	namespace brackets themselves must be a pair of outfix symbols
	which has been declared already, and are removed from the
	resulting expression. This works pretty much like a 'namespace'
	declaration, but only gives access to the public symbols of the
	namespace, and can be used anywhere inside an expression (even on
	the left-hand side of a rule). Nesting these constructs is also
	possible.

	Also, to accommodate these changes, the declaration syntax is now
	slightly more liberal in that qualified symbols are permitted in
	symbol and namespace declarations. (In the case of symbol and
	'using namespace' declarations, it will also be checked that
	qualified symbols are declared in or imported from the proper
	namespace.) This allows you to write stuff like:

	namespace faust with outfix faust::begin faust::end; end;
	namespace faust (faust::begin faust::end);

	which isn't possible without using namespace qualifiers because
	'end' by itself is a reserved keyword in Pure.

2012-06-28  Albert Graef  <Dr.Graef@t-online.de>

	* lexer.ll (docmd): Bugfixes and improvements in the interactive
	command parser. In particular, clear, dump and show will now
	complain about undefined symbols. This doesn't detect unmatched
	glob patterns and so isn't 100% foolproof, but it should catch
	most common errors and typos.

2012-06-27  Albert Graef  <Dr.Graef@t-online.de>

	* pure.cc: Add -e/--escape option and PURE_ESCAPE environment
	variable to switch on new escaped command syntax. Also fix up
	command completion accordingly.

	* lexer.ll, interpreter.cc/hh: Add support for escaped command
	syntax, as discussed on the mailing list. If this option is
	enabled, all interactive commands are prefixed with '!'. (This
	only applies to the command line, evalcmd works as before.)

2012-06-26  Albert Graef  <Dr.Graef@t-online.de>

	* examples/msort.pure: Added merge sort example by Jim Pryor.

	* configure.ac: Bump version number.

	* interpreter.cc (macspecial), symtable.cc/hh: Add a new built-in
	__gensym__ macro, per request by Jim Pryor. This enables you to
	create new, unqualified symbols on the fly, which is useful if a
	macro needs to generate block constructs such as lambdas and
	when/with clauses from scratch.

2012-06-25  Albert Graef  <Dr.Graef@t-online.de>

	* lib/matrices.pure: Experimental: As suggested by Jim Pryor, add
	non-splicing vector brackets as a shorthand notation for nested
	vectors.

	* runtime.cc (hash): Include environment in closure hashes (fixes
	second part of issue #82).

2012-06-24  Albert Graef  <Dr.Graef@t-online.de>

	* examples/do.pure: Add __do__ macro example from the Macros
	section of the manual.

	* runtime.cc (hash): Bogus assertion for anonymous closure (fixes
	issue #82 reported by Jim Pryor).

2012-06-20  Albert Graef  <Dr.Graef@t-online.de>

	* etc/pure.ssh: Added Eddie Rucker's a2ps style sheet for Pure.

2012-06-17  Albert Graef  <Dr.Graef@t-online.de>

	* interpreter.cc (quoted_tag): Missing "as" pattern in quoted
	pattern (fixes issue #79 reported by Jim Pryor).

2012-06-16  Albert Graef  <Dr.Graef@t-online.de>

	* interpreter.cc (macspecial): Leave the cases of __lambda__,
	__case__, __when__ and __with__ with an empty list argument
	undefined by the built-in macro rules (fixes issue #78 reported by
	Jim Pryor).

	* interpreter.cc (const_defn, clearsym): Make sure that we
	allocate a fresh expression pointer for each constant value cached
	in a read-only variable. This will leak a tiny amount of memory
	each time such a constant is redefined (which is possible using
	interactive commands and the introspection facilities), but this
	is needed to keep any dangling references to the constant intact.
	This fixes issue #77.

2012-06-15  Albert Graef  <Dr.Graef@t-online.de>

	* runtime.cc (get_funptr): get_funptr() might be invoked after a
	function was already purged from the environment.

2012-06-14  Albert Graef  <Dr.Graef@t-online.de>

	* interpreter.cc (checkfuns): Remove bogus assertion (issue #75).
	(next_statem): Missing case in code generation for matrix matching
	(issue #76). Reported by Jim Pryor.

2012-06-04  Albert Graef  <Dr.Graef@t-online.de>

	* 0.55 release.

	* interpreter.cc: Make clang and gfortran -fdragonegg the default
	compilers for inlined C/C++/Fortran code, as llvm-gcc isn't
	supported in the LLVM 3.x series any more.

2012-06-03  Albert Graef  <Dr.Graef@t-online.de>

	* configure.ac: Bump version number.

	* configure.ac, interpreter.cc: Add some options to deal with
	systems such as Mac OSX and Ubuntu which may have the LLVM
	toolchain and configure script installed under different prefixes,
	so that several LLVM versions can coexist on the same system.

	First, the configure option --with-tool-prefix allows to specify
	the prefix for the LLVM toolchain. This option, if specified, is
	also used to locate the llvm-config script, so that the proper
	LLVM version is selected.

	Second, the --with-llvm-version option allows to set the desired
	LLVM version, in which case configure tries to locate the
	llvm-config-<version> script on the PATH (after trying the tool
	prefix, if specified). If this option isn't specified, we default
	to looking for the llvm-config script on the PATH, which matches
	the behaviour in previous releases.

	If none of these yield a usable llvm-config script, we fall back
	to trying llvm-config-<version> for recent LLVM versions,
	preferring the latest version if found. Otherwise we give up and
	print an error message.

2012-06-02  Albert Graef  <Dr.Graef@t-online.de>

	* interpreter.cc/hh: Bugfix in type name resolution. Reported by
	Lucas Paul. Fixes issue #71.

2012-05-22  Albert Graef  <Dr.Graef@t-online.de>

	* Debian support: Add Debian packaging and a corresponding goal in
	the Makefile.

2012-05-19  Albert Graef  <Dr.Graef@t-online.de>

	* 0.54 release.

	* interpreter.cc (funsubstw): Fix clobbering of qualified symbols
	in the global namespace.

2012-05-15  Albert Graef  <Dr.Graef@t-online.de>

	* lib/prelude.pure: Fix up regression in optimization rules for
	list slices introduced in Pure 0.49. Reported by Yann Le Du.

2012-05-09  Albert Graef  <Dr.Graef@t-online.de>

	* configure.ac: Version bump.

	* interpreter.cc/hh, runtime.cc, pure.cc: LLVM 3.1 compatibility
	fixes.

2012-03-22  Albert Graef  <Dr.Graef@t-online.de>

	* 0.53 release.

	* runtime.cc (pure_sort): As suggested by Peter Summerland,
	optimize the case of POD types (int, bigint, double, string) in
	conjunction with the standard (<) and (>) predicates. In this case
	we don't actually have to invoke the Pure predicates, but can just
	execute the comparisons directly in C++. With int lists this gives
	a 10x speedup.

2012-03-08  Albert Graef  <Dr.Graef@t-online.de>

	* lexer.ll: Add -r and -s options to the trace command to switch
	between the new recursive and the previous skip tracing mode (see
	below).

	* interpreter.cc/hh, runtime.cc: Fix up function and macro call
	tracing to allow for recursive tracing of reductions while a
	tracepoint was invoked. Make this the default, as it's more useful
	in most situations.

2012-03-08  Albert Graef  <Dr.Graef@t-online.de>

	* 0.52 release.

	* lexer.ll (docmd): Add a -a option to the trace command which
	sets tracepoints on all (global) symbols.

2012-03-06  Albert Graef  <Dr.Graef@t-online.de>

	* Makefile.in: Fix a glitch causing discrepancies between
	generated log and actual test log for the prelude.

	* lib/prelude.pure: Fix up the definition of the __do__ macro for
	the reworked treatment of macro arguments.

	* interpreter.cc/hh, lexer.ll: Fixed some of the bad side-effects
	of autoquoting of macro arguments which would break macro hygiene.

	Implicit quoting of macro arguments is now disabled by default,
	and can be selectively enabled for individual macros with the new
	--quoteargs pragma. Also, autoquoted macro parameters are now
	actually quoted, i.e., embedded macro calls are not evaluated.

	This fixes name capture issues due to premature evaluation of
	embedded macros in quoted macro arguments. One minor defect which
	remains is the case of a free variable in a macro substition being
	captured by a local definition if the entire construct is quoted;
	see the last example in test078.pure. (One might argue, though,
	that in this specific case the behaviour of the macro evaluator is
	actually correct.)

2012-03-02  Albert Graef  <Dr.Graef@t-online.de>

	* runtime.cc: Update for the latest Faust revision after cleanup
	of the Faust UI data structures.

2012-02-20  Albert Graef  <Dr.Graef@t-online.de>

	* interpreter.cc (lcsubst): Added a missing recursion in the
	conditional, lambda, case, when and with cases. This fixes a
	failed assertion in the bind() method which could also occur, in
	particular, when processing comprehensions on the left-hand side
	of an equation or lambda. Reported by Richard Grossman.

2012-01-05  Albert Graef  <Dr.Graef@t-online.de>

	* parser.yy: Refactor some grammar rules so that some types of
	syntax errors in toplevel constructs are caught a bit earlier (see
	issue #69 reported by Jiri Spitz).