Pugs::Compiler::Rule - Compiler for Perl 6 regexes

This document describes Pugs::Compiler::Rule 0.28 released on 31 Oct, 2007.

Un-named rules are objects:

    use Pugs::Compiler::Rule;

    my $rule = Pugs::Compiler::Rule->compile( '((.).).' );
    my $match = $rule->match( 'abc' );

    if ($match) {               # true
        print $match;           # "abc"
        print $match->from;     # 0
        print $match->to;       # 3
        print $match->[0];      # "ab"
        print $match->[0][0];   # "a"
    }

Named rules are methods in a Grammar:

    package MyGrammar;
    use Pugs::Compiler::Rule;
    use base 'Pugs::Grammar::Base';

    Pugs::Compiler::Rule->install( rule => '((.).).' );
    my $match = MyGrammar->rule( 'abc' );

Rules may have parameters:

    $grammar->install(subrule => $source, { signature => $sig } );

    $grammar->install(rule => q{
            <subrule: param1, param2>
    });

where $grammar is normally a Perl 5 package.

This module provides an pure Perl 5 implementation for Perl 6 regexes, which does not depend on the Haskell Pugs.

It is a front-end to several other modules:

Front-end Modules

* Pugs::Compiler::Grammar compiles Perl 6 grammars to Perl 5.

* Pugs::Compiler::Rule compiles Perl 6 rules to Perl 5.

* Pugs::Compiler::Token compiles Perl 6 tokens to Perl 5.

* Pugs::Compiler::Regex compiles Perl 6 regexes to Perl 5.

* Pugs::Compiler::RegexPerl5 wraps Perl 5 regexes to return a Match object.

Runtime Classes

* Pugs::Runtime::Rule provides the runtime engine for Rules.

* Pugs::Runtime::Match represents a Match object.

* Pugs::Runtime::Grammar represents a Grammar class / object.

Grammars

* Pugs::Grammar::Rule parses the Rules syntax.

* Pugs::Grammar::Base is the base Grammar: <ws>, <space>.

Code Emitters

* Pugs::Emitter::Rule::Perl5 converts parsed Rules to Perl 5 code.

* Pugs::Emitter::Rule::Perl5::Ratchet converts parsed :ratchet Rules to Perl 5 code.

* Pugs::Emitter::Grammar::Perl5 converts parsed grammars to Perl 5 code.

  Pugs::Compiler::Rule
     isa Pugs::Compiler::Regex

This class (i.e. Pugs::Compiler::Rule) is a subclass of Pugs::Compiler::Regex and thus owns all the methods of its base class. See Pugs::Compiler::Regex for the detailed docs.

$rule = Pugs::Compiler::Rule->compile($p6_regex, $params)

Specifically, this class overrides the compile method of Pugs::Compiler::Regex which resets the following options' default values:

ratchet => 1

Here is an example:

    $rule = Pugs::Compiler::Rule->compile(
        'a*\w',
    );
    my $match = $rule->match('aaa');
    # $match->bool is false since no backtracking
    # happened

sigspace => 1

Here is an example:

    my $rule = Pugs::Compiler::Rule->compile(
        'a b',
    );
    my $match = $rule->match('a     b');
    ok $match->bool, 'sigspace works';
    is $match->(), 'a     b', 'sigspace works (2)';

This is an experimental development version. The API is still in flux.

The set of implemented features depend on the ratchet switch.

The Pugs Team <perl6-compiler@perl.org>.

Please join us on irc.freenode.net #perl6 if you'd like to participate.

• Pugs::Compiler::Regex
• Pugs::Compiler::Grammar
• compile_p6grammar.pl
• The Perl 6 Rules Spec: http://perlcabal.org/syn/S05.html

Copyright 2006, 2007 by Flavio Soibelmann Glock and others.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

See http://www.perl.com/perl/misc/Artistic.html