Parser Grammar Engine

The Parser Grammar Engine (PGE, originally the Parrot Grammar Engine) is a <a href="/facts/Compiler/WNfCDFJe">compiler</a> and <a href="/facts/Runtime_system/YmCuC4xP">runtime system</a> for <a href="/facts/Raku_rules/fHPb7SXl">Raku rules</a> for the <a href="/facts/Parrot_virtual_machine/tlcl5jAM">Parrot virtual machine</a>. PGE uses these rules to convert a <a href="/facts/Parsing_expression_grammar/8XdfJ7D0">parsing expression grammar</a> into Parrot <a href="/facts/Bytecode/EPkMFR7M">bytecode</a>. It is therefore compiling rules into a program, unlike most virtual machines and runtimes, which store regular expressions in a secondary internal format that is then interpreted at runtime by a regular expression engine. The rules format used by PGE can express any <a href="/facts/Regular_expression/KFL3veHX">regular expression</a> and most <a href="/facts/Formal_grammar/QLxaQNAz">formal grammars</a>, and as such it forms the first link in the compiler chain for all of Parrot's front-end languages.
When executed, the bytecode generated by PGE will parse text as described in the input rules, generating a parse tree. The parse tree can be manipulated directly, or fed into the next stage of the Parrot compiler toolchain to generate an <a href="/facts/Abstract_syntax_tree/73AUK1jI">abstract syntax tree</a> (AST) from which code can be generated; if the grammar describes a programming language.

Parser Grammar Engine open-in-new

Parser Grammar Engine