From: Stefan Monnier <monnier@iro.umontreal.ca>
To: emacs-devel@gnu.org
Subject: Re: [Emacs-diffs] master 05dc679: Turn on lexical-binding in json.el
Date: Thu, 11 Aug 2016 16:35:45 -0400 [thread overview]
Message-ID: <jwvinv79hdq.fsf-monnier+gmane.emacs.devel@gnu.org> (raw)
In-Reply-To: m2oa4zdxbq.fsf@newartisans.com
> in order to support dynamic binding. With lexical scoping enabled, and in the
> absence of closures, it should be possible to fully localize such references
> so that no lookup is performed at all.
Lexical variables aren't stored in symbols's slots, but in the byte-code
stack. So a variable access is an access to the (byte-code) stack with
a fixed offset. Not sure how much faster that makes it, tho.
> I'm not sure whether the byte-compiler makes use of such an
> optimization, or if we even have a byte-code operand to support it,
> but my unsupported guestimate is that we could double performance in
> most areas by properly utilizing lexical binding. Especially in tight
> loops that update/modify a local variable.
Lexical scoping does open up a fair bit of room for optimization,
indeed, and we haven't really tried to take advantage of it yet.
Stefan
next prev parent reply other threads:[~2016-08-11 20:35 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20160810044910.10174.12870@vcs.savannah.gnu.org>
[not found] ` <20160810044911.2B1C52201C2@vcs.savannah.gnu.org>
2016-08-10 15:45 ` [Emacs-diffs] master 05dc679: Turn on lexical-binding in json.el Stefan Monnier
2016-08-11 1:30 ` Mark Oteiza
2016-08-11 2:36 ` Stefan Monnier
2016-08-12 19:07 ` Stephen Berman
2016-08-12 19:43 ` Stefan Monnier
2016-08-13 18:18 ` [PATCH] lexical-binding mega-patch (was: Re: [Emacs-diffs] master 05dc679: Turn on lexical-binding in json.el) Mark Oteiza
2016-08-13 18:31 ` Eli Zaretskii
2016-08-14 6:32 ` [PATCH] lexical-binding mega-patch John Wiegley
2016-08-14 18:21 ` Mark Oteiza
2016-09-28 17:17 ` [PATCH] lexical-binding mega-patch (was: Re: [Emacs-diffs] master 05dc679: Turn on lexical-binding in json.el) Mark Oteiza
2016-09-29 15:21 ` Eli Zaretskii
2016-08-14 2:18 ` Chad Brown
2016-08-11 5:30 ` [Emacs-diffs] master 05dc679: Turn on lexical-binding in json.el Richard Stallman
2016-08-11 17:34 ` John Wiegley
2016-08-11 20:35 ` Stefan Monnier [this message]
2016-08-12 6:37 ` Eli Zaretskii
2016-08-12 12:41 ` Stefan Monnier
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