one more update. this is working as expected. $_[1] is a known database_id from iTunes...
my $library = $itunes->obj( 'playlist' => '1' ); my $tracks = $library->obj( 'tracks' => whose( 'database_id', 'equals', "$_[1]" )); if( $^E ) { $msg .= $^E; } else { for my $track ( $tracks->get() ) { $itunes->play( $track ); } } apparently "some track" in AppleScript can correspond to "tracks" with Mac::Glue. since there is only one result, the syntax looks funky but works. hopefully someone else learns something from this... =)