Re: Bugs caused by recent use of define-derived-mode

[Luc Teirlinck]

There are two questions raised by my previous bug report.  I only
address one here:

Is inheritance of abbrev tables desirable or needed?  Inheritance of
abbrev tables would essentially be equivalent to the introduction of
"recursively super-local abbrevs".  I doubt I would use such a feature
myself.  Of course everybody may have his or her own ways to use
local abbrevs and maybe other people could find it useful.  

As long as inheritance of abbrevs would be defined in a bug-free way
that does not inconvenience anybody who does not want to use it, it
would of course be perfectly OK to do that.  Note however, that this
would require additional changes, for instance in the way 
M-x list-abbrevs lists abbrevs (otherwise, it would get hopelessly
cluttered by countlessly repeated abbrev definitions).

To me, it seems like a lot of work with very little benefit, but, of
course, other people can disagree with me on that.

The fact is though that currently we do not have inheritance of
abbrevs.  I believe that the current "poor man's inheritance" is an
unacceptable alternative.  It makes a lottery out of abbrev expansion.

If we decide NOT to go for true inheritance, or at least not in the
very immediate future, then it seems clear to me that closely related
modes should use the same abbrev-table.  As long as there is no true
inheritance I consider the existence of a
paragraph-indent-text-mode-abbrev-table an "annoying feature" (to
avoid the b-word).

Stefan's patch takes indeed care of the mail-mode-abbrev-table bug  (I
can safely use the b-word here, since Stefan actually agreed it was a
bug.)  There actually was a related "nuisance feature" for
syntax-tables, but since Stefan's patch can be used for that one too,
I do not see any reason to expand on this. 

One last remark:

Stefan Monnier wrote:

   I'm not sure it's correct.  There has already been people on
   gnu.emacs.help asking why they can't define abbrevs that are
   specific to their mail buffers.

Are you sure they were asking that because they really wanted that
feature or because they were confused by the fact that mailabbrev.el
mistakenly claimed that there was a mail-mode-abbrev-table?

Sincerely,

Luc.