Re: Default lexical-binding to t

[Eli Zaretskii]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: rms@gnu.org,  emacs-devel@gnu.org
> Date: Wed, 06 Nov 2024 07:50:43 -0500
> 
> > Consider the plight of someone who over the years have accrued
> > hundreds of lines of Lisp in their init and customization files, and
> > now needs somehow to walk over all of that and see if anything needs
> > changing, or risk breakage in something that has been working for
> > eons.  It would be nice if we could help those poor souls, and not
> > just hang them to dry.
> 
> They should likely add a `lexical-binding:nil` cookie and move on.

In each and every file?  Not a simple thing to do.

> Of course, they can also change this cookie to `t` temporarily every
> once in a while to see if it uncovers a problem or not, so the
> conversion can be done bit by bit.

For some code that gets executed only rarely, this is not practical.

Can you tell what are the benefits of turning on lexical-binding by
default, relative to what we have now?  Which files/uses are affected,
and how?  Maybe if we see all the potential effects, we could find a
nicer way forward.