Re: What's the error in this macro?

On Sat, 21 Sep 2024 13:29:23 +0000, B. Pym wrote:

KK wrote:
>

(defmacro sum (expression index initial condition)
;; Sum $expression$ for $index$ = $initial$ and successive integers,
;; as long as $condition$ holds.
  (let ((temp (gensym)))
    `(do ((,temp 0 (+ ,temp ,expression))
          (,index ,initial (1+ ,index)))
         ((not ,condition) ,temp))))

        This looks good to me...  Was this the corrected version?

>
The main error with this macro is that it does something you could do
with the standard LOOP. I.e. instead of debugging this macro, you could
be working on the program where this macro is intended to be used:
>

>

 (loop for x from 1 while (< x 6) summing x)    --> 15

>
Gauche Scheme
>
(use srfi-42) ;; sum-ec
(sum-ec (:range x 1 6) x)        ===>      15

In Scheme and  Gauche Scheme,   do ppl use  Gensym?
(define-macro (Sum expression index initial condition)
              `(do ((%Sum 0 (+ %Sum ,expression))
                    (,index ,initial (+ 1 ,index)))
                 ((not ,condition) %Sum)))
(print (macroexpand '(Sum  x  x 1 (< x 6))))
(print (Sum  x  x 1 (< x 6)))