Path: news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail
From: "B. Pym" <Nobody447095@here-nor-there.org>
Newsgroups: comp.lang.lisp
Subject: Re: Illegal LOOP usage?
Date: Wed, 18 Jun 2025 21:57:34 -0000 (UTC)
Organization: A noiseless patient Spider
Lines: 43
Message-ID: <102vcoa$3dbeg$1@dont-email.me>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Injection-Date: Wed, 18 Jun 2025 23:57:34 +0200 (CEST)
Injection-Info: dont-email.me; posting-host="faeb3e276463c6d792453c53fb61f4b5";
	logging-data="3583440"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX1/xzXNPKxurQrnvVs4g882N"
User-Agent: XanaNews/1.18.1.6
Cancel-Lock: sha1:ZQtZQDcnE1eDHxcbSzcnHiBvtLM=

Edi Weitz wrote:

> So, this function from Drakma
> 
>   (defun split-string (string &optional (separators " ,-"))
>     "Splits STRING into substrings separated by the characters in the
>   sequence SEPARATORS.  Empty substrings aren't collected."
>     (loop for char across string
>           when (find char separators :test #'char=)
>           when collector
>           collect (coerce collector 'string) into result
>           and do (setq collector nil) end
>           else
>           collect char into collector
>           finally (return (if collector
>                             (append result (list (coerce collector 'string)))
>                             result))))
> 
> works as intended with LispWorks, but doesn't work with AllegroCL or
> SBCL.  It seems the latter two simply ignore the (SETQ COLLECTOR NIL)
> form.  My guess is that the code above is somehow incorrect in that it
> modifies a variable which is used in a "collect ... into ..." clause,
> but I couldn't find anything in the CLHS that explicitly says so.
> 
> Any hints?

Gauche Scheme

(use srfi-13)  ;; string-tokenize
(use srfi-14)  ;; character sets

(define (split-string strng :optional (separators " ,-"))
  (define good-chars
    (char-set-complement (string->char-set separators)))
  (string-tokenize strng good-chars))

(split-string " foo   bar-baz--zoo,,sooth,,,")
  ===>
("foo" "bar" "baz" "zoo" "sooth")

(split-string " foo   bar-baz--zoo,,sooth,,,"  " o")
  ===>
("f" "bar-baz--z" ",,s" "th,,,")