Gambit's unquote-splicing ignores the end of improper lists (when splicing into the middle of a list): > `(hello ,@"hmm" well) (hello well) > `(hello (unquote-splicing '("hmm" . "and")) well) (hello "hmm" well) Scheme-48 and Chicken throw an error in this case. Is there a reason an error should not be thrown? Christian.