Congratulations, you have found the most ugly Lisp code ever. > so I can't judge whether the author of this code actually knows what they're doing Not really.

Congratulations, you have found the most ugly Lisp code ever. > so I can't judge whether the author of this code actually knows what they're doing Not really. He can't even format the code. For example from that blog post: (defun return_highers_helper (list element result) (cond ((null list) result) ((equalp (first element) (first (first list))) (cond ((< (rest element) (rest(car list))) (return_highers_helper (cdr list) element (cons (car list) result))) (t (return_highers_helper (cdr list) element result)) )) (t (return_highers_helper (cdr list) element result)) )) This would be written usually as: (defun %return-highers (element list) (remove-if-not (lambda (item) (and (equalp (car element) (car item)) (< (cdr element) (cdr item)))) list))