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  • Committer: Bazaar Package Importer
  • Author(s): Carlo Segre
  • Date: 2008-02-23 23:13:02 UTC
  • mfrom: (2.1.2 hardy)
  • Revision ID: james.westby@ubuntu.com-20080223231302-mnyyxs3icvrus4ke
Tags: 066-3
Apply patch to athena_parts/misc.pl for compatibility with 
perl-tk 804.28.

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0CPAN/Parse-RecDescent-1.94/demo/demo_selfmod.pl
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#! /usr/local/bin/perl -sw
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# A SELF-MODIFYING**2 PARSER
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use Parse::RecDescent;
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$grammar =
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q{
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        type_defn : 'only' <commit> "$::keyword" is type_name ';'
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                       { $thisparser->Replace("type_name: '$item[5]'");
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                          print "\"$item[5]\" is now the only valid type name\n";
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                       }
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                  | "$::keyword" <commit> identifier(s) is type_name /('?s)?/ ';'
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                       { my $newnames = join " | ", map { "'$_'" } @{$item[3]};
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                          $thisparser->Extend("type_name: $newnames"); 
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                          print "added $newnames as type name(s)\n";
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                       }
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                  | /change\s+$::keyword\s+to/ identifier
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                       { $::keyword = $item[2];
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                          print "changed $item[0] keyword to: $item[2]\n";
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                       }
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                  | <error>
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        is        : /is|are/
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        type_name : 'int' | 'float' 
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        identifier: ...!is ...!"$::keyword" ...!type_name /[A-Za-z]\w*/
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};
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use vars qw { $keyword };
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$keyword = "type";
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$parse = new Parse::RecDescent ($grammar);
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while (<>)
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{
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        $parse->type_defn($_) or print "huh?\n";
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}