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From: Alan Mackenzie <acm@muc.de>
To: Stefan Monnier <monnier@iro.umontreal.ca>
Cc: emacs-devel@gnu.org
Subject: Re: Lexical binding: why?
Date: Tue, 28 May 2019 17:41:27 +0000	[thread overview]
Message-ID: <20190528174127.GC5296@ACM> (raw)
In-Reply-To: <jwvimtuv6mk.fsf-monnier+emacs@gnu.org>

Hello, Stefan.

On Tue, May 28, 2019 at 13:21:22 -0400, Stefan Monnier wrote:
> > Just in passing2, it seems to be difficult to enable lexical binding
> > conditionally.  The best that I can come up with is something like:

> > -*- eval: (setq lexical-binding (> emacs-major-version 25)) -*-

> Hmm... why do you need that?  Is that because of a performance problem
> in Emacs-24's lexical-binding support (likely the one that affects
> condition-case and friends)?

I was thinking more of a bug, since fixed, in older versions of the
lexical-binding code.  Purely hypothetically at the moment, of course.
But this code is surely not so simple that bugs can be ruled out.

But performance problems in older versions of l-b would also be a reason.

For consistency with other features, which can all be enabled
conditionally, surely lexical-binding should also be conditionally
enablable in a reasonable way.

>         Stefan

-- 
Alan Mackenzie (Nuremberg, Germany).



  reply	other threads:[~2019-05-28 17:41 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-28 10:08 Lexical binding: why? Alan Mackenzie
2019-05-28 12:01 ` Tadeus Prastowo
2019-05-28 12:26 ` Stefan Monnier
2019-05-28 13:02   ` Dmitry Gutov
2019-05-28 13:25     ` Stefan Monnier
2019-05-28 13:46       ` Dmitry Gutov
2019-05-28 13:44   ` Alan Mackenzie
2019-05-28 17:21     ` Stefan Monnier
2019-05-28 17:41       ` Alan Mackenzie [this message]
2019-05-28 17:58         ` Stefan Monnier
2019-05-28 15:19 ` John Wiegley

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