;;;
;;; Splits a string into tokens delimited by a set of characters
;;; specified by another string.
;;;
;;; Dan Cross <net!gajendra!cross>
;;;
(defun split-on (delims string)
  "Split the string 'string' on any of the characters in 'delims'
   and return the results.  Ignores empty fields."
  (labels ((isdelim (c) (position c delims))
           (span-delims (string start)
             (when (and string start)
               (position-if-not #'isdelim string :start start)))
           (span-not-delims (string start)
             (when (and string start)
               (position-if #'isdelim string :start start))))
    (loop for b = (span-delims string 0)
       then (span-delims string (1+ f))
       as f = (span-not-delims string b)
       when b collect (subseq string b f)
       while f)))