Re: elisp mouse programming problems

[Kevin Rodgers]

David Vanderschel wrote:

> "Alex Schroeder" <alex@emacswiki.org> wrote in message
> 873cfwvcqp.fsf@emacswiki.org">news:873cfwvcqp.fsf@emacswiki.org...
>
> > "David Vanderschel" <DJV1@Austin.RR.com> writes:
> > > Also, in testing such things, I am confused by the
> > > fact that I cannot seem to redefine the bindings of a
> > > mode-map by simply setting it to nil and rerunning the
> > > (modified) code which builds the mode-map.  ...
> >
> > A keymap is a list that starts with the symbol `keymap'.
> > Only the cdr of that list is used by Emacs when
> > looking up keys.  When you just change the value of a
> > mode-map, the old cdr will still be used.  (Maybe you
> > need to draw box diagrams to see this.)
>
> When I said "setting it to nil" I was talking about
> the pointer to the list (Hube-mode-map, in my case).
> Thus regenerating that list should also generate a new
> cdr.  If emacs still has a pointer to the old cdr, I
> need to know how to get emacs to give it up.  What
> makes it adopt the cdr in the first place?
>
> I think I have now figured this one out.  Changing the
> mode-map itself is not sufficient.  You must again
> invoke (use-local-map whatever-mode-map).


That is not true.  As Alex explained, when you modify the keymap, you
are modifying a part of its list structure that is shared by the
variable and the mode.

> (I had
> erroneously believed that what emacs remembered was my
> variable which held the pointer to the mode-map and
> that it would use the new map when I changed it.  But
> there is no quote on the argument, so it cannot know.
> I now recall running into another manifestation of
> this.  emacs will readily show you the current
> mode-map, but it is difficult to discover the 'name'
> of that map - ie., the variable used to create it.)

That is true, but it's not relevant. 


--
Kevin Rodgers