Re: Lexical binding: why?

[Alan Mackenzie <acm@muc.de>]

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).