From: Stefan Monnier <monnier@iro.umontreal.ca>
To: emacs-devel@gnu.org
Cc: "Mattias Engdegård" <mattiase@acm.org>
Subject: Re: master 68c09c6: Better CPS conversion of multi-binding `let`
Date: Tue, 30 Nov 2021 08:19:19 -0500 [thread overview]
Message-ID: <jwvczmhlr5g.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: <20211130120405.6C5F4209FD@vcs0.savannah.gnu.org> ("Mattias Engdegård"'s message of "Tue, 30 Nov 2021 07:04:05 -0500 (EST)")
> - ;; 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
next parent reply other threads:[~2021-11-30 13:19 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20211130120404.23495.29099@vcs0.savannah.gnu.org>
[not found] ` <20211130120405.6C5F4209FD@vcs0.savannah.gnu.org>
2021-11-30 13:19 ` Stefan Monnier [this message]
2021-11-30 13:30 ` master 68c09c6: Better CPS conversion of multi-binding `let` Mattias Engdegård
2021-11-30 13:42 ` Stefan Monnier
2021-11-30 13:49 ` Mattias Engdegård
2021-11-30 13:54 ` Stefan Monnier
2021-11-30 14:11 ` Mattias Engdegård
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