RE: linum.el -- Display line numbers to the left of buffers

[Drew Adams]

> > Writers of libraries that are not part of the Emacs distribution
> > are often more concerned about compatibility for users of
> > different releases and even different flavors of Emacs
> > (e.g. XEmacs).
>
> They might be concerned, yes, but I don't think anyone can dictate
> that a package author mustkeep their code backwards compatible -- even
> when it _is_ possible.

I certainly didn't mean to dictate any such thing to anyone.

> If the package author want to do so, it is ok,

Thanks!

> but for the specific
> case of linum.el, alternative packages already exist which works ok
> with older Emacsen, so why look back, rather than look forwards, and
> provide some _new_ features for the latest and greatest Emacs?

As you say, it's up to the package writer. I'd say that what Markus did in
the latest version was what I would suggest, if a writer has the time and
the will: make the library useful with various versions, but let it take
advantage of recent features for recent versions.

It takes a little more work (sometimes a lot more work) to do that, but I,
for one, appreciate it. And, as I said before, for some libraries it makes
little sense to try to be backward compatible. I think linum.el might become
the general replacement for setnu.el and other packages, for old Emacs
versions as well as for new ones.

You are right that linum.el could take advantage of even more Emacs 22
features. And you (and Leo) are right that that would help test Emacs 22 and
would help us discover new things we can do with the new features. That
doesn't preclude making the basic functionality available also to users of
older Emacs versions - provided that Markus has the time and will to do
that.