Stefan Monnier <[EMAIL PROTECTED]> writes:
[...]
> if I have function FOO autoloaded and (require 'blabla) replaces
> that with some other definition, than an immediately following
> (unload-feature 'blabla) should restore the autoload, no matter
> whether the autoload was pointing to blabla.el or not.
I have thought about this some more and there's more to it than just
autoloads.
What currently happens when you do (require 'blabla) and then
(unload-feature 'blabla) is that all functions that "blabla" defined
are unbound. Maybe not the right thing to do, but quite consistent.
(There is only one case where (unload-feature 'blabla) will do
anything else then fmakunbound a function that "blabla" defined and
that is when a function was autoloaded and that function was defined
when do_autoload loaded "blabla".)
Consider the following situation:
function 'a is autoloaded: (autoload "blabla" ...).
function 'b is autoloaded: (autoload "other" ...).
function 'c is defined.
function 'd is unbound.
"blabla" defines 'a, 'b, 'c, and 'd as functions.
Do (require 'blabla) and then (unload-feature 'blabla).
Currently, all four functions will be unbound by unload-feature. You
propose to let unload-feature restore both 'a and 'b to their previous
autoloads [1]. But what should be done with 'c?
I think restoring 'c to its previous definition would be the right
thing to do. But that would be quite a substantial change. It's
probably best to leave this alone until after the release.
Lute.
[1] I have actually implemented this for Frequire; it's quite simple:
Index: src/fns.c
===================================================================
RCS file: /cvsroot/emacs/emacs/src/fns.c,v
retrieving revision 1.389
diff -c -r1.389 fns.c
*** src/fns.c 22 Apr 2005 07:11:08 -0000 1.389
--- src/fns.c 24 Apr 2005 20:06:44 -0000
***************
*** 3482,3487 ****
--- 3482,3488 ----
if (NILP (tem))
{
+ Lisp_Object first, second;
int count = SPECPDL_INDEX ();
int nesting = 0;
***************
*** 3528,3533 ****
--- 3529,3551 ----
error ("Required feature `%s' was not provided",
SDATA (SYMBOL_NAME (feature)));
+ /* Save the old autoloads, in case we ever do an unload. */
+ tem = Vautoload_queue;
+ while (CONSP (tem))
+ {
+ first = XCAR (tem);
+ second = Fcdr (first);
+ first = Fcar (first);
+
+ /* Note: This test is subtle. The cdr of an autoload-queue entry
+ may be an atom if the autoload entry was generated by a defalias
+ or fset. */
+ if (CONSP (second))
+ Fput (first, Qautoload, (XCDR (second)));
+
+ tem = XCDR (tem);
+ }
+
/* Once loading finishes, don't undo it. */
Vautoload_queue = Qt;
feature = unbind_to (count, feature);
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