#!/usr/bin/env perl
use strict;
use warnings;
use Parse::RecDescent;
use Data::Dumper;

my $grammar = <<'END';

   foo: word(s)
   word:
      /\S+/
      {
         push @{$thisparser->{local}}, lc $item[1];
         $return = uc $item[1];
      }

END

my $parser = Parse::RecDescent->new($grammar);
my $what   = $parser->foo("Foo bAr baZ");
print Dumper $what, $parser->{local};

__END__
$VAR1 = [
          'FOO',
          'BAR',
          'BAZ'
        ];
$VAR2 = [
          'foo',
          'bar',
          'baz'
        ];