DSSSL Library Reference: Part of the Modular DocBook Stylesheet distribution
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# strip

## Name

strip -- Strip leading and trailing characters off of a string

## Synopsis

    (strip str #!optional (stripchars '(#\space #\
     #\U-0009)))

## Description

Strips leading and trailing characters in the `stripchars` list off of a string and returns the stripped string.

`str`

  The string to strip

`stripchars`

  A list of characters that should be stripped.

## Author

Norman Walsh, <ndw@nwalsh.com>

## Source Code

    (define (strip str #!optional (stripchars '(#\space #\
     #\U-0009)))
      ;; Strip leading and trailing characters off of a string
      (let* ((startpos (let loop ((count 0))
    		     (if (>= count (string-length str))
    			 (string-length str)
    			 (if (member (string-ref str count) stripchars)
    			     (loop (+ count 1))
    			     count))))
    	 (tailstr  (substring str startpos (string-length str)))
    	 (endpos   (let loop ((count (- (string-length tailstr) 1)))
    		     (if (< count 1)
    			 0
    			 (if (member (string-ref tailstr count) stripchars)
    			     (loop (- count 1))
    			     count)))))
        (if (equal? endpos 0)
    	""
    	(substring tailstr 0 (+ endpos 1)))))

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