Re: Extended menu items, when are :enable and :filter computed?

[Stefan Monnier]

>     I don't think this is considered as a feature (and I thought it was in
>     the TODO list to change it so that submenus are only constructed when
>     needed, but I can't seem to find it in the TODO file),

> The reason for precomputing all the submenus is so that the toolkit
> can display them all autonomously.  I think that's the only way some
> toolkits can do it, so the idea of changing this is a non-starter.

If the only toolkits which could do it are non-free or "insignificant", then
I agree, but otherwise it may still make sense to provide it as
a toolkit-dependent optimization.  But indeed, it means that even if we
manage to change it for some toolkits, you won't be able to rely on
your :filters and :enables being called only when strictly necessary.

I've always viewed such a change as a performance improvement for those
cases where we use large dynamically-generated menus or menus with lots of
shortcuts to compute (X-Symbol comes to mind).

AFAIK XEmacs does compute menus on-demand.


        Stefan