Here are some functions I've written to convert strings into
lists of various sorts. Examples follow at the end.

(defun list-from-string (string
&key
(start 0)
(char-bag '(#\Space))
(test #'(lambda (ch)
(not (member ch char-bag
:test 'char=))))
(post-process 'identity))
(let ((pos (position-if test string :start start)))
(if pos
(list-from-string* string :start pos :char-bag char-bag
:test test :post-process post-process)
nil)))

(defun list-from-string* (string
&key
(start 0)
(char-bag '(#\Space))
(test #'(lambda (ch)
(not (member ch char-bag :test 'char=))))
(post-process 'identity))
(let* ((pos (position-if-not test string :start start))
(new-pos (if pos (position-if test string :start pos) nil)))
(cond
((and pos new-pos)
(cons (funcall post-process (subseq string start pos))
(list-from-string* string :start new-pos :char-bag char-bag
:test test :post-process post-process)))
(pos (list (funcall post-process (subseq string start pos))))

(t (list (funcall post-process (subseq string start)))))))

....

(list-from-string "chris! dan! ski! elaine! nick!"
:char-bag '(#\Space #\!)) -->
("chris" "dan" "ski" "elaine" "nick")

Gauche Scheme

(use srfi-13)
(use srfi-14)

(string-tokenize
" chris!..?..!dan!ski!;elaine! nick! "
char-set:letter)

===>
("chris" "dan" "ski" "elaine" "nick")

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