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 Pugs::Grammar::Base;

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

DESCRIPTION

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

* 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::Rule::Rule specifies the Rules syntax with Rules.

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

* Code Emitters

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

Implemented Features

<ws> 
#comment\n 
. 
? * + *? +? ??
literal
[] 
()     
|

<'literal'>
<subrule>
<namespace::subrule>
<$var>      
<?subrule>
<!subrule>

<@var>             -- special-cased for array-of-rule (but not Rule|Str)
\char              -- not all chars implemented
{code}             -- non-capturing closure
                   -- perl5 syntax inside closure
                   -- $/ doesn't work yet
{ return code }    -- capturing closure
                   -- perl5 syntax inside closure
                   -- $/ works
$var := (capture)  -- capture aliasing
$<> $/<>           -- special variables can't be used inside a match yet
$/ 
$<0> $<1>
$0 $1
\n \N

Unimplemented Features

$variable 
@variable
$/<0> $/<1>
$/0 $/1
<"literal">
^ ^^ $ $$
<unicode-class> <+unicode-class> <+unicode-class+unicode-class>
<&var> 
<%var>
**{n..m}
: :: :::   (commit)
$var := [non-capture]
$var := <rule>
<(closure-assertion)> <{code-returns-rule}>
<<character-class>> <[character-class]>
:flag :flag() :flag[]
lookahead lookbehind
\x0a \0123 ...
&    

METHODS

compile (Str $rule_source)

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.

match (Str $match_against)

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

perl5

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

CAVEATS

This is an experimental development version. There are currently no support for match flags, and the API is still in flux.

It is currently unsuitable for just about any use other than Pugs development. Please join us on irc.freenode.net #perl6 if you'd like to participate. :-)

AUTHORS

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

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