NAME

Pugs::Grammar::Precedence - Engine for Perl 6 Rule operator precedence

SYNOPSIS

  use Pugs::Grammar::Precedence;

  # example definition for "sub rxinfix:<|> ..."

  my $rxinfix = Pugs::Grammar::Precedence->new(
    grammar => 'rxinfix',
  );
  $rxinfix->add_op(
    name => '|',
    assoc => 'left',
    fixity => 'infix',
  );

Pseudo-code for usage inside a grammar:

    sub new_proto( $match ) {
        return ${$match<category>}.add_op(
            name => $match<name>,
            fixity => ...,
            precedence => ...,
        );
    }

    rule prototype {
        proto <category>:<name> <options>
        {
            return new_proto($/);
        }
    }

    rule statement {
        <category.parse> ...
    }

DESCRIPTION

This module provides an implementation for Perl 6 operator precedence.

METHODS

new ()

Class method. Returns a category object.

options:

•: "grammar => $category_name" - the name of this category (a namespace or a Grammar name).

add_op ()

Instance method. Adds a new operator to the category.

options:

name => $operator_name - the name of this operator, such as '+', '*'

name2 => $operator_name - the name of the second operator in an operator pair, such as circumfix [ '(', ')' ] or ternary [ '??', '!!' ].

 # precedence=>'tighter',
 #   tighter/looser/equiv
 # other=>'+',
 # fixity =>
 #  infix/prefix/circumfix/postcircumfix/ternary
 # assoc =>
 #  left/right/non/chain/list
 # rule=>$rule
 #  (is parsed)

AUTHORS

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

COPYRIGHT

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>