Re: How to find when a function/var has been added

[Stephen Leake <stephen_leake@stephe-leake.org>]

Przemysław Wojnowski <esperanto@cumego.com> writes:

>> I think maybe Przemysław is asking for something more, including
>> changes to the default value or possible values of an option, and
>> changes to the behavior or at least the calling sequence of an
>> existing function.
>>
>> Dunno how much would be feasible or what forms it might take, but
>> I agree that there is a use case for it.
>>
> I was thinking about adding "Since: ${emacs-version}" to docs of
> functions and variables just to make it easier to write backward
> compatible packages.
>
> If I would like to preserve compatibility with Emacs 24.3.1 I wouldn't
> use newer functions/values. Now it is not that easy (at least for me)
> to find out since when a function/variable/package is in Emacs, which
> makes programming a bit slower.

I write and test the code for Emacs 25, then byte-compile in Emacs 24;
that identifies the functions/variables that need attention. Unless
there's some function that changed behavior without any other change; we
usually treat that as a bug, unless the change is actually fixing a bug.

Adding emacs version info to _all_ definitions would be tedious; there
would be a very small chance that any particular bit would be needed.
That's not true for customize, since those are user-visible things.

-- 
-- Stephe