Re: defcustom :version

[Luc Teirlinck]

Bill Wohler wrote:

   Unless, of course, folks think is reasonable and proper that large
   independent packages that happen to be bundled with Emacs can use their
   versions with the defcustom :version keyword.

No, because that would give problems with `customize-changed'.  For
packages included with the Emacs distribution the :version keyword
should be the first released version of Emacs that contains the
defcustom with its current standard value.  Note however that a
defcustom needs no :version keyword if the :version is the same as
that of the defgroup.  Defcustoms in packages not distributed with
Emacs should have no :version keyword.

`M-x customize-changed RET 21.4 RET' is supposed to show the user all
defcustoms that were added, or whose standard value changed, in Emacs
22.1.  That is the main purpose of the :version keyword.  Of course,
the fact that you get a 2811 line long Custom buffer limits the
usefulness of this feature.  Once upon a time, when Emacs releases
used to be much more frequent than they are now, `M-x customize-changed'
was one of the most useful things to do when a new Emacs version came out.

Sincerely,

Luc.