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#! /usr/local/bin/perl -sw
# DEMONSTRATE USING DERIVED CLASS METHODS IN A PARSER
package MyParser;
use Parse::RecDescent;
@ISA = qw { Parse::RecDescent };
# CALL THIS METHOD THROUGH AN OBJECT...
sub print_cat ($$)
{
print "CAT: $_[1]\n";
}
# CALL THESE METHODS DIRECTLY (MUST QUALIFY)...
sub print_dog ($)
{
print "DOG: $_[0]\n";
}
sub print_rat ($)
{
print "RAT: $_[0]\n";
}
package main;
$grammar =
q{
inputs : input(s) | <reject>
input : "cat"
{ $thisparser->print_cat($item[1]); }
| "dog"
{ MyParser::print_dog($item[1]); }
| "rat"
# ERROR (UNQUALIFIED METHOD CALL)
{ print_rat($item[1]); }
};
$parse = new MyParser ($grammar);
print "> ";
while (<>)
{
$parse->inputs($_) || print "huh?\n";
print "> ";
}
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