On Thu, 2002-05-09 at 20:30, Richard Stallman wrote:

> The easiest way to implement these functions will often be to use
> a category property.  Then these functions can simply change the
> properties of the category, and faces will appear or disappear all thru
> the buffer.
> 
> In fact, it might make sense to have a buffer-local variable
> font-lock-category-alist whose elements look like (CATEGORY-SYMBOL .
> FACE-PROP).  

This solution is genius!  I didn't understand it at all at first, so I
sort of deferred trying to implement it, but after discovering the
`category' text property in the elisp manual it made sense.

Please find attached a patch which implements it, and changes Info,
shell (via comint), occur, and ibuffer to use it.  

I believe this patch addresses everyone's issues.   In particular,
font-core.el is very small, and it is efficient (no runtime searching
for text properties).  

Really, I think info.el should be changed to use a
`font-lock-fontify-region' function; `Info-fontify-maximum-menu-size'
could then just go away.