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