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

[Luc Teirlinck <teirllm@dms.auburn.edu>]

   > 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.

   Again, please show us examples.

C-x b text
M-x text-mode
Type:
William
C-x a l bob
Type:
Robert
C-x a l bob
Redefine?
y
C-x b pidtext
M-x paragraph-indent-text-mode
Type:
bob
C-x '
Expansion: Robert.
Wonderful.

Start the exercise over, say with a new emacs.

C-x b text
M-x text-mode
Type:
William
C-x a l bob
C-x b pidtext1
M-x paragraph-indent-text-mode
C-x k
(Back in buffer text)
Type:
Robert
C-x a l bob
Redefine?
y
C-x b pidtext2
M-x paragraph-indent-text-mode
Type:
bob
C-x '
Expansion: William
Less wonderful

There are several variations on this.  The "real" example of this is,
of course, in a long editing session where you do not remember which
files or buffers you visited when and in which mode.  Then it becomes
a lottery.

I could tell you what causes this bug, but I believe you will have no
difficulty figuring that out yourself.  The really difficult thing is
to fix this bug, without introducing others to replace it.  I believe
this is essentially equivalent with defining true inheritance.

Sincerely,

Luc.