#: re/re.pm#: Regexp emitter for re#: Copyright (c) 2006 Agent Zhang#: 2006-05-13 2006-05-15package re::re;use strict;use warnings;#use Data::Dumper::Simple;use re::AST;use re::Parser;use Language::AttributeGrammar;#use Scalar::Util qw( looks_like_number );sub translate {    my ($self, $src) = @_;    #warn $src;    my $parser = re::Parser->new() or die "Can't construct the parser!\n";    my $ptree = $parser->program($src) or return undef;    return $self->emit($ptree);}sub emit {    my ($self, $ptree) = @_;    #$Data::Dumper::Indent = 1;    #warn Dumper($ptree);    $re::re::emit::grammar ||= new Language::AttributeGrammar <<'END_GRAMMAR';program:    $/.re = { $<expression>.re }expression: $/.re = { $<alternation>.re }alternation:     $/.re = { re::re::emit_alternation( $<alternation>.re, $<concat>.re ) }concat:     $/.re = { $<concat>.re . $<modified_atom>.re }modified_atom:  $/.re = { $<atom>.re . $<modifier>.re; }atom:           $/.re = { re::re::emit_atom( $<child>.re ) }modifier:       $/.re = { $<__VALUE__> }char:           $/.re = { $<__VALUE__> }nil:        $/.re = { '' }END_GRAMMAR    $re::re::emit::grammar->apply($ptree, 're');}sub emit_alternation {    my ($a, $b) = @_;    if ($a) {        "$a|$b";    } else {        $b;    }}sub emit_atom {    my ($re) = @_;    if ($re =~ /^(?:\\.|[^*|()])$/ or $re =~ /^\(.*\)$/) {        $re;    } else {        "($re)";    }}1;__END__