Re: (dsssl) Substring manipulation?

[Jany Quintard <quintard.j@xxxxxxxxxx>]

On Fri, 2 Feb 2001, David Perrin wrote:

> Hi there,
> 
> Trying to use the substring function but having a tough time determining the
> function to use to calculate the start position.
> 
Excuse me David, but I did not check properly what I wrote in my previous
mail.
The find-first-char is NOT want you want. The proc can anyway give you
ideas. For your problem, you can try the function hereafter (untested).
This one returns -1 if the string does not contain any colon and the index
of the position of the first colon otherwise.

(define (position-of-colon strParam)
  (let (max (- (string-length strParam) 1) ;; first index is 0

    (let loop ((strParam strParam)
               (index 0))
    
      (if (> index max)   ;; colon is not in the string
          -1
          (if (equal? (string-ref strParam index) #\;)
              index   ;; found
              (loop strParam (+ 1 index))))))) ;; looping further
Jany

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           and do not necessarily represent those of IBM.
------------------------------------------------------------------------
Jany Quintard                                 | Spam :
IBM Paris Laboratory                          | Spiced Pork And Ham, a sort
Application & Integration Middleware Division | of cheap luncheon meat.



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