bug#59333: [PATCH] Define macro dlet*

[Jean Louis <bugs@gnu.support>]

* daanturo <daanturo@gmail.com> [2022-11-17 10:16]:
> --=-=-=
> Content-Type: text/plain
> 
> Tags: patch
> 
> 
> The dlet breakage comes as much surprise to me. There's not even a
> single entry in NEWS that mentions it.

If I remember well, `dlet' was working just fine (as in the sense of
dlet*), and then because it was changed and made `dlet' behave not in
the sense of `dlet*', it did not work any more for me, so I have
renamed the old dlet, to my private function `rcd-dlet' to fix it's
behavior when developers changed the last line.

The last line of `dlet' is now:  (let ,binders ,@body))) while I need
it to be as below:      (let* ,binders ,@body)))

(defmacro rcd-dlet (binders &rest body)
  "Like `let*' but using dynamic scoping.

Argument BINDERS behaves similarly like `let' with the difference
that variables become global even under lexical scope.

Optional argument BODY will be executed."
  (declare (indent 1) (debug let))
  ;; (defvar FOO) only affects the current scope, but in order for
  ;; this not to affect code after the main `let' we need to create a new scope,
  ;; which is what the surrounding `let' is for.
  ;; FIXME: (let () ...) currently doesn't actually create a new scope,
  ;; which is why we use (let (_) ...).
  `(let (_)
     ,@(mapcar (lambda (binder)
                 `(defvar ,(if (consp binder) (car binder) binder)))
               binders)
     (let* ,binders ,@body)))


-- 
Jean

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