Combining face and map stuff

[Lars Magne Ingebrigtsen]

It would often be convenient to say "this region should be in bold" and
"this partially overlapping region should also be italic", and so on.
I've been looking in the Emacs Lisp manual, but I can't find any utility
functions for doing stuff like that.  They all seem to start with a face
with some properties that you apply to a text, which isn't really what I
want.  So I would kinda of like...  a function that took a face, and
then "combined" it with any faces that were already in the region.
Possible?

Which reminds me of another thing.  I would like to define some commands
local to a region, which can be done with 'local-map in overlays or
'keymap in text properties.  But can I combine them, too, in possibly
overlapping regions, and get the aggregate keymap?

-- 
(domestic pets only, the antidote for overdose, milk.)
  address@hidden * Lars Magne Ingebrigtsen