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Subject: Join
Date: Sun, 14 Jul 2024 09:03:11 -0000 (UTC)
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Adam Warner wrote:

> Hi Lowell Kirsh, 
> 
> > I want to write a function to take a list of strings and a delimiter and 
> > return a string with the strings put together with the delimiter as glue. 
> 
> > e.g. (join '("foo" "bar" "baz")) -> "foo:bar:baz" 
> 
> (defun join (list &optional (delimiter #\:)) 
>   (let ((countdown (length list))) 
>     (with-output-to-string (stream) 
>       (dolist (item list) 
>         (write-string item stream) 
>         (decf countdown) 
>         (unless (zerop countdown) 
>           (write-char delimiter stream))))))

Gauche Scheme

(define (join lst :optional (delimiter #\,))
  (with-output-to-string
    (lambda()
      (display (car lst))
      (for-each
        (cut format #t "~a~a" delimiter <>)
        (cdr lst)))))