Re: How to cast an imperative loop into a readable recursive function ?

[Pascal J. Bourguignon]

Katalin Sinkov <lispstylist@gmail.com> writes:

> Take a look at my lisp code. it can be modified simply to run it and
> it runs in an emacs "ide".

No it does not.  


First, it's lacking a parenthesis.

You should get paredit.el, and activate the paredit-mode to edit lisp
sources.  See how lisp code is indented, and let emacs and paredit
indent it for you, and place the parentheses for you.  This will produce
lisp code that is more readable, and you will be able to copy-and-paste
sexps "structurally", with much less risk of losing parentheses.



Then, if we add the obvious missing parenthesis, and try to evaluate
your code:


    (let ((char_skips (- n  s) ))
      (while (not (= char_skips 0))
        (progn
          (if (<= char_skips (+ l -1) )
              (progn
                (forward-char char_skips)
                (setq char_skips 0))
              (progn
                (forward-char l)

                (forward-search-regexp "(s=###l=###)" nil nil nil) ; put in an 
if
                ;; and else block to test if FAIL
                (setq s (match-string 0))
                (setq l (match-string 0))

                (setq char_skips (- n s) ))))))


we get the following error:

    Debugger entered--Lisp error: (void-variable n)
      (- n s)
      (let ((char_skips ...)) (while (not ...) (progn ...)))
      eval((let ((char_skips ...)) (while (not ...) (progn ...))))
      eval-last-sexp-1(nil)
      eval-last-sexp(nil)
      call-interactively(eval-last-sexp nil nil)


If you want us to help, please provide working stand alone code, with
test data.

(By the way, my emacs "23.2.1" doesn't have a forward-search-regexp
function).


-- 
__Pascal Bourguignon__                     http://www.informatimago.com/
A bad day in () is better than a good day in {}.