trAvis - MANAGER

Edit File: demo_selfmod.pl

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