use Data::Dumper qw( Dumper );
use Parse::RecDescent ();

my $p = Parse::RecDescent->new(<<'__END_OF_GRAMMAR__');
parse : /a*/ /a/ /\Z/ { [ $item[1], $item[2] ] }
__END_OF_GRAMMAR__

print(Dumper($p->parse('aaaaa')));