NAME

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

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>
});

DESCRIPTION

This module provides an implementation for Perl 6 Rules. It is a front-end to several other modules:

Front-end Modules

• 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.

METHODS

compile (Str $rule_source, \%options)

Class method. Returns a compiled rule object, or throws an exception on invalid rule syntax.

options:

• grammar => $class

  Specify which namespace (Grammar) the rule belongs to.

• ratchet => 1

  Disable backtracking. Match faster. Defaults to 1 in Rules and Tokens.

• pos => $pos

  Specify a string position to match. Starts in zero. Defaults to undef, which matches anywhere in the string.

• sigspace => 1

  Whitespace is significant. Defaults to 1 in Rules.

• ignorecase => 1

  Ignore character case. The default is significant case.

• Perl5 => 1

  Use Perl 5 grammar and semantics for Regex.

match (Str $match_against)

Instance method. Returns a Pugs::Runtime::Match object.

install (Str $name, Str $rule_source, \%options)

Install a rule into the method $name. If $name is fully qualified then it will be installed into that path e.g MyGrammar::rulename, otherwise it will install it into the current package.

perl

Instance method. Returns a string that can be eval'ed into a rule/token/regex object.

CAVEATS

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

The set of implemented features depends 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

The Perl 6 Rules Spec: http://dev.perl.org/perl6/doc/design/syn/S05.html

COPYRIGHT

Copyright 2006 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

cpanm Pugs::Compiler::Rule

perl -MCPAN -e shell
install Pugs::Compiler::Rule