Re: master 68c09c6: Better CPS conversion of multi-binding `let`

[Stefan Monnier <monnier@iro.umontreal.ca>]

> -    ;; Process `let' in a helper function that transforms it into a
> -    ;; let* with temporaries.
> +    (`(,(or 'let 'let*) () . ,body)
> +      (cps--transform-1 `(progn ,@body) next-state))
> +
> +    (`(let (,binding) . ,body)
> +      (cps--transform-1 `(let* (,binding) ,@body) next-state))
> +
> +    ;; Transform multi-variable `let' into `let*':
> +    ;;    (let ((v1 e1) ... (vN eN)) BODY)
> +    ;; -> (let* ((t1 e1) ... (tN eN) (v1 t1) (vN tN)) BODY)

I think this optimization can be generalized to the multi-var case by
noticing that the transformation of (vN eN) into a pair (tN eN) ... (vN tN)
is not necessary because the order of the (v1 t1) ... (vN tN) doesn't matter
so we can move (vN tN) to the beginning, right next to (tN eN) and then
merge them back.


        Stefan