Rainer Joswig wrote:

> (defun split-string (string &optional (separators " ,-"))
> "Splits STRING into a list of substrings (which is returned)
> separated by the characters in the sequence SEPARATORS. Empty
> substrings aren't collected."
> (flet ((make-collector ()
> (make-array 0
> :adjustable t
> :fill-pointer t
> :element-type #+:lispworks 'lw:simple-char
> #-:lispworks 'character)))
> (loop with collector = (make-collector)
> for char across string
> for counter downfrom (1- (length string))
> when (find char separators :test #'char=)
> when (plusp (length collector))
> collect collector
> and do (setq collector (make-collector))
> (vector-push-extend char collector)
> else do (vector-push-extend char collector) end
> else
> do (vector-push-extend char collector)
> and when (zerop counter) collect collector)))
>

(use srfi-13) ;; string-fold for Gauche Scheme
or
(require srfi/13) ;; string-fold for Racket

(define (string-split-inclusive str . chars)
(reverse
(filter-map (lambda (xs)
(and (pair? xs) (apply string (reverse xs))))
(string-fold
(lambda (c accum)
(if (member c chars)
(cons (list c) accum)
(cons (cons c (car accum)) (cdr accum))))
'(())
str))))

(string-split-inclusive "" #\; #\,)
===>
()

(string-split-inclusive ";foo,bar;baz;" #\; #\,)
===>
(";foo" ",bar" ";baz" ";")
(";foo" ",bar" ";baz" ";")

(string-split-inclusive "{pal}{buddy}{/buddy}{/pal}" #\{)
===>
("{pal}" "{buddy}" "{/buddy}" "{/pal}")