More Lisp

Still like Lisp, even after 6 days. Wrote my first useable program with it today. I am still discovering it, but I wrote a cool little function:

(defun explode-to-list (expr str &optional &key (s nil))
  (let ((size (search expr str)))
    (if size 
	(explode-to-list expr (subseq str (+ 1 size)) 
		 :s (append s (list (subseq str 0 size))))	
      (append s (list (subseq str 0))))))

It takes a string like (explode "," "foo,bar.bin") and returns the list ("foo" "bar" "bin")

This might not be right, and there is probably a better way to do this, but I am really having fun.