Re: Fwd: overlay face property not used for after-string property

[Joe Wells <jbw@macs.hw.ac.uk>]

Richard Stallman <rms@gnu.org> writes:

>     > The fix we are discussing will get rid of this problem, right?
>
>     No, the problem with the before-string/display/after-string
>     properties being affected by a face from the buffer appears to
>     be a completely unrelated issue which will need to be debugged
>     separately.
>
> I see.  We have one problem with overlay properties, and
> another with text properties.
>
> I think I just fixed the most of the problem for overlay
> properties.  Now overlay before-strings and after-strings should be
> unaffected by the face properties of all overlays.  They are,
> however, affected by `face' text properties and by region
> highlighting.
>
> It is not 100% clear that that is correct; you might want a longer
> overlay's `face' property, or a higher priority overlay's `face'
> property, to affect the before-strings and after-strings of smaller
> overlays.

This is a very good point!

> That seems like somewhat of a can of worms.  The rule I implemented
> is simple and clear.
>
> Do you agree?

I agree that it is simple and clear.  However, given the point you
made above, I think it would be better if before-string and
after-string properties were affected by the face property of other
overlays (regardless of whether they should be affected by the face
property of the same overlay).

> And do you get good results from the fix?  (It is in Emacs 22.)

I will not be able to test in a new Emacs version in the near future.

> Do you think the same rule is right for display property strings that
> come from overlays?  That is, obey `face' text properties, but not
> `face' overlay properties?

No.

> Once we are sure what is right for overlay properties, I will start
> dealing with the text property effects.

By the way, the concern I raise in the message you quote above is not
about text properties in the before-string or after-string, but about
text properties in the buffer.

-- 
Joe