Re: Does seq.el need to work with older Emacs versions?

[Stefan Kangas]

Philip Kaludercic <philipk@posteo.net> writes:

> ELPA's seq currently only consists of the following
>
> --8<---------------cut here---------------start------------->8---
> (if (version< emacs-version "25")
>     (require 'seq-24)
>   (require 'seq-25))
> --8<---------------cut here---------------end--------------->8---
>
> where seq-24.el is a compatibility version, while seq-25.el appears to
> be the same as lisp/emacs-lisp/seq.el (or at least the version from a
> year ago).  What I guess this means is that lisp/emacs-lisp/seq.el
> should preserve compatibility up until Emacs 25, unless another
> backport version should be added to the ELPA package.

Unlike other core packages, seq.el is manually merged to GNU ELPA.  So
we can be flexible when we decide how to go about it.

Before breaking backwards compatibility with Emacs 25, perhaps it would
be a good idea to update seq-25.el on GNU ELPA to match what we
currently have on master.

We could then always,

    (if (version< emacs-version "29") ; or something
        (require 'seq-25)
      (require 'seq-29))

or even,

    (cond ((version< emacs-version "25") (require seq-24))
          ((version< emacs-version "29") (require seq-25))
          (t (require seq-29)))

And then update "Package-Requires" accordingly.

As for going forward, I guess it is somewhat nice to maintain backwards
compatibility.  But I don't know if it's worth doing indefinitely.