# Parrot Virtual Machine/Built-In PMCs
## Built-in PMCs

Parrot ships with a number of PMC data types built in. This means that these standard types are always available. This page is going to serve as a reference to these PMC types. We will not attempt to cover all the PMC types that are added specifically for other HLLs, libraries, or programs. (For information on using these PMC types, and on defining new PMC types, see the Parrot Virtual Machine/Polymorphic Containers (PMCs) chapter).
The entries in this list should (A) contain a link to the relevant PMC documentation, and (B) provide a brief overview of the PMC and it's methods.

### AddrRegistry

* http://docs.parrot.org/parrot/latest/html/src/pmc/addrregistry.pmc.html

### Array

* http://www.parrotcode.org/docs/pmc/pmc/array.html
A simple array class, serves as the base class for other array PMCs. This type of PMC is rarely used directly. Instead, more versatile array PMC types, such as ResizablePMCArray are used. Array specifies an interface that all other Array classes must share. It also provides a number of defaults that other array-like PMCs may default to.

### BigInt

* http://docs.parrot.org/parrot/latest/html/src/pmc/bignum.pmc.html
A PMC type for storing an arbitrarily large number, or a number with arbitrary precision. Not currently implemented.

### Boolean

* http://docs.parrot.org/parrot/latest/html/src/pmc/boolean.pmc.html
A boolean True/False PMC.

### Bound_NCI

* http://www.parrotcode.org/docs/pmc/pmc/bound_nci.html

### Capture

* http://docs.parrot.org/parrot/latest/html/src/pmc/capture.pmc.html

### Closure

* http://www.parrotcode.org/docs/pmc/pmc/closure.html

### Compiler

* http://www.parrotcode.org/docs/pmc/pmc/compiler.html
A Compiler PMC for a particular language. Can be used to convert an HLL into PIR and eventually into Parrot Bytecode.

### Complex

* http://www.parrotcode.org/docs/pmc/pmc/complex.html
A PMC for Complex numbers.

### Continuation

* http://www.parrotcode.org/docs/pmc/pmc/continuation.html
A Continuation PMC allows Parrot to take a snapshot of the current state of the system to return to later.

### Coroutine

* http://www.parrotcode.org/docs/pmc/pmc/coroutine.html
A sub-like PMC that implements a coroutine.

### Default

* http://www.parrotcode.org/docs/pmc/pmc/default.html

### Deleg_PMC

* http://www.parrotcode.org/docs/pmc/pmc/deleg_pmc.html

### Delegate

* http://www.parrotcode.org/docs/pmc/pmc/delegate .html

### Enumerate

* http://www.parrotcode.org/docs/pmc/pmc/enumerate.html

### Env

* http://www.parrotcode.org/docs/pmc/pmc/env.html
Allows access to the system's environment variables, as a hash.

### Eval

* http://www.parrotcode.org/docs/pmc/pmc/eval.html

### Exception

* http://www.parrotcode.org/docs/pmc/pmc/exception.html
An Exception PMC holds information about system errors for recovery.

### Exception_Handler

* http://www.parrotcode.org/docs/pmc/pmc/exception_handler.html
A sub-like routine that catches and resolves exceptions

### Exporter

* http://www.parrotcode.org/docs/pmc/pmc/exporter.html

### File

* http://docs.parrot.org/parrot/latest/html/src/dynpmc/file.pmc.html
A read/write interface for files

### FixedBooleanArray

* http://www.parrotcode.org/docs/pmc/pmc/fixedbooleanarray.html
An array of fixed size of Boolean values.

### FixedFloatArray

* http://www.parrotcode.org/docs/pmc/pmc/fixedfloatarray.html
An array of fixed size for FLOATVAL floating point numbers

### FixedPMCArray

* http://www.parrotcode.org/docs/pmc/pmc/fixedpmcarray.html
An array of fixed size for PMC values

### FixedStringArray

* http://www.parrotcode.org/docs/pmc/pmc/fixedstringarray.html
An array of fixed size for STRING values

### Float

* http://www.parrotcode.org/docs/pmc/pmc/float.html
A floating point number PMC. Used similarly to a FLOATVAL, except has methods and vtable methods. FLOATVALs become Float PMCs when they are promoted to become a PMC.

### Hash

* http://www.parrotcode.org/docs/pmc/pmc/hash.html
A hash, also known as a "dictionary" or an "associative array". Like an array but indexed with strings instead of integers

### Integer

* http://www.parrotcode.org/docs/pmc/pmc/integer.html
A basic integer number PMC. Used similarly to an INTVAL, but with methods and vtable methods. INTVALS become Integer PMCs when they are promoted to become a PMC.

### IntList

* http://www.parrotcode.org/docs/pmc/pmc/intlist.html
A simple list, or array, of integers.

### Iterator

* http://www.parrotcode.org/docs/pmc/pmc/iterator.html
An Iterator PMC provides a stateful counter that enables you to iterate over the items in one of the array classes, one at a time.

### Key

* http://www.parrotcode.org/docs/pmc/pmc/key.html
A value, typically a string, which is used to look up values in a hash.

### LexInfo

* http://www.parrotcode.org/docs/pmc/pmc/lexinfo.html

### LexPad

* http://www.parrotcode.org/docs/pmc/pmc/lexpad.html

### ManagedStruct

* http://www.parrotcode.org/docs/pmc/pmc/managedstruct.html
A low-level structure whose memory is allocated and automatically deallocated by Parrot. Extends UnManagedStruct, but adds automatic memory collection.

### MultiArray

* http://www.parrotcode.org/docs/pmc/pmc/multiarray.html

### MultiSub

* http://www.parrotcode.org/docs/pmc/pmc/multisub.html
A collection of subroutines with the same name. In Multiple Method Dispatch (MMD) the parameters of the function called determine which subroutine from the collection to call.

### Namespace

* http://www.parrotcode.org/docs/pmc/pmc/namespace.html
Implements a Parrot namespace. Contains information about variables, subroutines, coroutines, and MultiSubs that are stored in that namespace.

### NCI

* http://www.parrotcode.org/docs/pmc/pmc/nci.html
A native call function PMC. Stores interface information to a function which has been written in C.

### Null

* http://www.parrotcode.org/docs/pmc/pmc/null.html
A PMC with a NUL value

### Object

* http://www.parrotcode.org/docs/pmc/pmc/object.html

### OrderedHash

* http://www.parrotcode.org/docs/pmc/pmc/orderedhash.html

### OS

* http://www.parrotcode.org/docs/pmc/pmc/os.html

### Pair

* http://www.parrotcode.org/docs/pmc/pmc/pair.html
An association of a Key PMC with a PMC value. Hashes are typically implemented as an array of Pair PMCs

### ParrotClass

* http://www.parrotcode.org/docs/pmc/pmc/parrotclass.html

### ParrotInterpreter

* http://www.parrotcode.org/docs/pmc/pmc/parrotinterpreter.html
An interface to the interpreter structure.

### ParrotIO

* http://www.parrotcode.org/docs/pmc/pmc/parrotio.html
A read/write interface to the console

### ParrotLibrary

* http://www.parrotcode.org/docs/pmc/pmc/parrotlibrary.html
A dynamically-loaded library object.

### ParrotObject

* http://www.parrotcode.org/docs/pmc/pmc/parrotobject.html

### ParrotRunningThread

* http://www.parrotcode.org/docs/pmc/pmc/parrotrunningthread.html

### ParrotThread

* http://www.parrotcode.org/docs/pmc/pmc/parrotthread.html
A PMC that stores information about a thread

### Pmethod_test

* http://www.parrotcode.org/docs/pmc/pmc/pmethod_test.html

### Pointer

* http://www.parrotcode.org/docs/pmc/pmc/pointer.html

### Random

* http://www.parrotcode.org/docs/pmc/pmc/random.html

### Ref

* http://www.parrotcode.org/docs/pmc/pmc/ref.html

### ResizableBooleanArray

* http://www.parrotcode.org/docs/pmc/pmc/resizablebooleanarray.html
A resizable array to store Boolean values

### ResizableFloatArray

* http://www.parrotcode.org/docs/pmc/pmc/resizablefloatarray.html
A resizable array to store floating point values.

### ResizableIntegerArray

* http://www.parrotcode.org/docs/pmc/pmc/resizableintegerarray.html
A resizable array to store integer values

### ResizablePMCArray

* http://www.parrotcode.org/docs/pmc/pmc/resizablepmcarray.html
A resizable array to store PMC values

### ResizableStringArray

* http://www.parrotcode.org/docs/pmc/pmc/resizablestringarray.html
A resizable array to store Strings

### RetContinuation

* http://www.parrotcode.org/docs/pmc/pmc/retcontinuation.html
A return continuation. Like a regular Continuation PMC, but can only be used once. Can be promoted to a Continuation using the Clone vtable method.

### Role

* http://www.parrotcode.org/docs/pmc/pmc/role.html
An abstract role, or interface, for a class. Specifies actions and properties of a class, but cannot be instantiated

### SArray

* http://www.parrotcode.org/docs/pmc/pmc/sarray.html

### SharedRef

* http://www.parrotcode.org/docs/pmc/pmc/sharedref.html

### Slice

* http://www.parrotcode.org/docs/pmc/pmc/slice.html

### SMOP_Attribute

* http://www.parrotcode.org/docs/pmc/pmc/smop_attribute.html

### SMOP_Class

* http://www.parrotcode.org/docs/pmc/pmc/smop_class.html

### STMLog

* http://www.parrotcode.org/docs/pmc/pmc/stmlog.html

### STMRef

* http://www.parrotcode.org/docs/pmc/pmc/stmref.html

### STMVar

* http://www.parrotcode.org/docs/pmc/pmc/stmvar.html

### String

* http://www.parrotcode.org/docs/pmc/pmc/string.html
A PMC to contain a string value. Like a STRING value, but has methods and vtable methods. STRINGS become String PMCs when they are promoted to PMCs.

### Sub

* http://www.parrotcode.org/docs/pmc/pmc/sub.html
A Parrot subroutine. Implements a basic subroutine (using the sub command in PIR), but also serves as a base class for more intricate sub-like classes

### Super

* http://www.parrotcode.org/docs/pmc/pmc/super.html
A parent PMC class, to support multiple inheritance.

### Timer

* http://www.parrotcode.org/docs/pmc/pmc/timer.html

### TQueue

* http://www.parrotcode.org/docs/pmc/pmc/tqueue.html

### Undef

* http://www.parrotcode.org/docs/pmc/pmc/undef.html
An undefined PMC with no usable type.

### UnamangedStruct

* http://www.parrotcode.org/docs/pmc/pmc/unamangedstruct.html
A low-level structure which the programmer must manage manually. Parrot does not automatically collect memory allocated for the struct.

### Version

* http://www.parrotcode.org/docs/pmc/pmc/version.html