Re: Proposal: Forwards-Compatibility Library for Emacs

[João Távora]

On Wed, Sep 22, 2021 at 7:53 AM Philip Kaludercic <philipk@posteo.net> wrote:

> This might work for subr-x and other elisp packages (in which case these
> could just be added as dependencies to the effectively virtual package
> compat).

Yes, correct.  So my next ELPA package would just Package-Require: the
ELPA package compat, which would bring in "lots of compatibility" (though
not 100% right away).

> On the other hand: If the functions are implemented in C, then they have
> to be replicated some other way. And this doesn't just apply to
> length{<,=,>}, string-distance, etc. but any function that might end up
> using them down the call stack.

Those could be isolated in some "cshims.el" package.  I don't know
if they would effectively be dependencies of lots of other packages.
It depends.

> In principle, these two approaches can be merged,

Yes, correct, the two approaches should be merged, and my feeling
is that your approach is useful mostly to fill the gaps where the current
one doesn't cut it.

> but I have the impression that this would be more complicated

Funny, I have the opposite feeling.  I think it would be simpler, since
for some high percentage of cases just Package-Require-ing some
:core packages by domain  would be enough for the Emacs versions
that you wish to support.  Certainly with Eglot, a fairly complex package
it has been (mostly) [*] the case, but then again Eglot only goes back to
26.3.

João

*: "mostly", because we indeed have our shim for "executable-find" there.
"executable-find" comes from "files.el", so maybe we could just
Package-Require it?