Perl virtual machine: Difference between revisions

Revision as of 19:42, 24 July 2010

Revision as of 01:20, 1 September 2010

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{{Expert-subject|Free Software}}

The '''Perl virtual machine''' is a [[Stack machine|stack-based]] [[Application virtual machine|process virtual machine]] implemented as [[opcode|opcodes]] [[Interpreter (computing)|interpreter]] which runs a previously compiled [[Perl]] programs. Opcodes interpreter is a part of Perl interpreter which contains also [[Compiler|compiler]] ([[Lexical analysis|lexer]], [[Parsing|parser]] and [[Compiler optimization|optimizer]]) in one executable file, commonly /usr/bin/perl on various [[Unix-like]] systems or perl.exe on [[Microsoft Windows]] systems.

==Implementation==

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Perl uses a reference count-driven garbage collection mechanism. SVs, AVs, or HVs start their life with a reference count of 1. If the reference count of a data value ever drops to 0, then it will be destroyed and its memory made available for reuse.

Other typedefs are Glob Value (''GV'') which contains named references to the various objects, Code Value (''CV'') which contains a reference to Perl subroutine, I/O Handler (''IO''), a reference to [[Regular expression|regular expression]] (''REGEXP''; ''RV'' in Perl before 5.11), reference to compiled format for output record (''FM'') and simple reference which is a special type of scalar that point to other data types (''RV'').

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