Parrot virtual machine

Parrot virtual machine
Parrot virtual machine
Parrot Foundation logo
Developer(s) Parrot Foundation
Stable release 3.10.0[1] / November 16, 2011; 7 days ago (2011-11-16)[1]
Written in C
Operating system Cross-platform
Type Virtual machine
License Artistic License 2.0

Parrot is a register-based process virtual machine designed to run dynamic languages efficiently. It uses just-in-time compilation for speed to reduce the interpretation overhead. It is currently possible to compile Parrot assembly language and PIR (an intermediate language) to Parrot bytecode and execute it. Parrot is free and open source software.[2]

Parrot was started by the Perl community and is developed with help from the open source and free software communities. As a result, it is focused on license compatibility (Artistic License 2.0), platform compatibility across a broad array of systems, processor architecture compatibility across most modern processors, speed of execution, small size (around 700k depending on platform), and the flexibility to handle the varying demands that Perl 6, and most other modern dynamic languages make. Other goals include improving introspection, debugger capabilities, and compile-time semantic modulation.[clarification needed]

Version 1.0, with a stable API for development, was released on March 17, 2009.[3] The current stable production release of Parrot is version 3.10.0 "Apple Pi", released on November 16, 2011.[1]



The name Parrot came from an April Fool's joke which announced a hypothetical language, named Parrot, that would unify Python and Perl.[4][5] The name was later adopted by this project (initially a part of the Perl 6 development effort) which aims to support Perl 6, Python, and other programming languages. Several languages are being ported to run on the Parrot virtual machine.[6]

The Parrot Foundation was created in 2008 to hold the copyright and trademarks of the Parrot project, to help drive development of language implementations and the core codebase, to provide a base for growing the Parrot community, and to reach out to other language communities.[7]


The goal of the Parrot virtual machine is to host client languages and allow inter-operation between them. Several hurdles exist in accomplishing this goal, in particular the difficulty of mapping high-level concepts, data, and data structures between languages.

Static and dynamic languages

The differing properties of statically and dynamically typed languages have motivated the design of Parrot. Current popular virtual machines such as the Java virtual machine and the Common Language Runtime have been designed for statically typed languages, while the languages targeted by Parrot are dynamically typed.

Virtual machines such as the Java virtual machine and the current Perl 5 virtual machine are also stack based. Parrot developers see Parrot's inclusion of registers as an advantage, as it therefore more closely resembles a hardware design, allowing the vast literature on compiler optimization to be used in generating bytecode for the Parrot virtual machine that could run at speeds closer to machine code. Other register-based virtual machines have inspired parts of Parrot's design, including the Lua VM and Inferno's Dis.

Functional concepts

Parrot has rich support for several features of functional programming including closures and continuations, both of which can be particularly difficult to implement correctly and portably, especially in conjunction with exception handling and threading. Implementing solutions to these problems at the virtual machine level prevents repeated efforts to solve these problems in the individual client languages.

Compiler tools

Parrot provides a suite of compiler-writing tools[8] which includes the Parser Grammar Engine (PGE), a hybrid parser-generator that can express a recursive descent parser as well as a operator-precedence parser, allowing free transition between the two in a single grammar. The PGE feeds into the Tree Grammar Engine (TGE) which further transforms the parse-tree generated by PGE for optimization and ultimately for code generation.

Existing client languages

Many languages already have compiler front-ends designed for Parrot; however, many of them are still only partially functional.[9] The languages currently implementable, partially and fully, on Parrot are:[10]


There are three forms of program code for Parrot:

PIR transparently manages Parrot's inter-routine calling conventions, provides improved syntax, register allocation, and more. PIR code is usually stored in files with the filename extension ".pir".



Parrot is register-based like most hardware CPUs, and unlike most virtual machines, which are stack-based. Parrot provides four types of registers:

Parrot provides an arbitrary number of registers; this number is fixed at compile time per subroutine.

Arithmetic operations


   set I1, 4
   inc I1        # I1 is now 5
   add I1, 2     # I1 is now 7
   set N1, 42.0
   dec N1        # N1 is now 41.0
   sub N1, 2.0   # N1 is now 39.0
   print I1
   print ', '
   print N1
   print "\n"


.sub 'main' :main
   $I1 = 4
   inc $I1     # $I1 is now 5
   $I1 += 2    # $I1 is now 7
   $N1 = 42.0
   dec $N1     # $N1 is now 41.0
   $N1 -= 2.0  # $N1 now 39.0
   print $I1
   print ', '
   print $N1
   print "\n"


Until late 2005, Dan Sugalski was the lead designer and chief architect of Parrot. Chip Salzenberg, a longtime Perl, Linux kernel, and C++ hacker, took over until mid-2006, when he became the lead developer. Allison Randal, the lead developer of Punie and chief architect of Parrot's compiler tools, was the chief architect until mid-October 2010 when she stepped down and chose Christoph Otto as the new chief architect.[15]

Development discussions take place primarily on the #parrot channel on In addition, there are weekly moderated meetings for Parrot and language developers hosted in #parrotsketch on the same network. Much discussion also occurs on the parrot-dev mailing list, hosted by

Design discussions exist in the form of Parrot Design Documents, or PDDs, in the Parrot repository.[16] The chief architect or another designated designer produces these documents to explain the philosophy of a feature as well as its interface and design notes. Parrot hackers turn these documents into executable tests, and then existing features.

The Parrot team releases a new stable version of the software on the third Tuesday of every month. Core committers take turns producing releases in a revolving schedule, where no single committer is responsible for multiple releases in a row. This practice has improved the project's velocity and stability.

See also


External links

Wikimedia Foundation. 2010.

Игры ⚽ Нужно решить контрольную?

Look at other dictionaries:

  • Parrot virtual machine — Parrot Cette page d’homonymie répertorie les différents sujets et articles partageant un même nom.  Pour l’article homophone, voir Parot. Sommaire 1 …   Wikipédia en Français

  • Virtual machine — A virtual machine (VM) is a completely isolated guest operating system installation within a normal host operating system .[1] Modern virtual machines are implemented with either software emulation or hardware virtualization or (in the most… …   Wikipedia

  • Virtual Machine — Machine virtuelle Pour les articles homonymes, voir VM. VirtualBox Le sens originel de machine virtuelle (ou Virtual Machine (VM) en anglais) e …   Wikipédia en Français

  • Java Virtual Machine — A Java Virtual Machine (JVM) is a set of computer software programs and data structures which use a virtual machine model for the execution of other computer programs and scripts. The model used by a JVM accepts a form of computer intermediate… …   Wikipedia

  • Virtual Machine — virtuelle Maschine in VirtualBox Eine virtuelle Maschine, kurz VM, ist ein virtueller Computer. Auf einem realen Computer können gleichzeitig mehrere virtuelle Maschinen betrieben werden. Virtuelle Maschinen werden als Betriebssystem ausgeführt,… …   Deutsch Wikipedia

  • Virtual Machine Monitor — virtuelle Maschine in VirtualBox Eine virtuelle Maschine, kurz VM, ist ein virtueller Computer. Auf einem realen Computer können gleichzeitig mehrere virtuelle Maschinen betrieben werden. Virtuelle Maschinen werden als Betriebssystem ausgeführt,… …   Deutsch Wikipedia

  • Java Virtual Machine — В этой статье не хватает ссылок на источники информации. Информация должна быть проверяема, иначе она может быть поставлена под сомнение и удалена. Вы можете …   Википедия

  • Parrot (disambiguation) — Parrot can refer to:* Parrots (psittacines), any of about 353 species of bird belonging to the biological order Psittaciformes, which includes: **True parrots **Cockatoos * Psittacosis (parrot disease or parrot fever), an infectious disease of… …   Wikipedia

  • Parrot — Тип виртуальная машина Разработчик The Perl Foundation Операционная система Кроссплатформенное программное обеспечение Последняя версия 4.6.0 (16 июля …   Википедия

  • Parrot assembly language — The Parrot assembly language or PASM is the basic assembly language used by the Parrot virtual machine, a part of the Perl 6 project.PASM is the lowest level assembly language. The Parrot intermediate representation or PIR is PASM, extended to… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”