NAME

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

VERSION

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

SYNOPSIS

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.

DESCRIPTION

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.

INHERITANCE

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

METHODS

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)';

CAVEATS

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

The set of implemented features depend on the "ratchet" switch.

AUTHORS

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

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

SEE ALSO

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

COPYRIGHT

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>