Re: Re: Support (or not) for Emacs 21, and XEmacs

[Michael Sperber <sperber@deinprogramm.de>]

Carsten Dominik <carsten.dominik@gmail.com> writes:

> That is acceptable - but I think that making BUFFER default to
> (current-buffer) does make a lot of sense - which is why making that
> argument optional in XEmacs is a good idea anyway.

It would - but the problem is that in XEmacs, an omitted BUFFER argument
means something different from (current-buffer):

`local-variable-p' is a built-in function
  -- loaded from "/afs/informatik.uni-tuebingen.de/home/sperber/build/xemacs/src/symbols.c"
(local-variable-p SYMBOL BUFFER &optional AFTER-SET)

Documentation:
Return t if SYMBOL's value is local to BUFFER.
If optional third arg AFTER-SET is non-nil, return t if SYMBOL would be
buffer-local after it is set, regardless of whether it is so presently.
A nil value for BUFFER is *not* the same as (current-buffer), but means
"no buffer".  Specifically:

-- If BUFFER is nil and AFTER-SET is nil, a return value of t indicates that
   the variable is one of the special built-in variables that is always
   buffer-local. (This includes `buffer-file-name', `buffer-read-only',
   `buffer-undo-list', and others.)

-- If BUFFER is nil and AFTER-SET is t, a return value of t indicates that
   the variable has had `make-variable-buffer-local' applied to it.

-- 
Cheers =8-} Mike
Friede, Völkerverständigung und überhaupt blabla