# 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 "> ";
    }