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

[Joe Wells]

Richard Stallman <address@hidden> writes:

>     > Can someone write a patch so that the overlay's face property (and
>     > other display-related properties) won't apply to its before-string?
>     >
>     > Joe, what do you think about that as a solution?
>
>     I think that would be an improvement.  I think the best solution would
>     be for the face property of an overlay (and similar properties) to not
>     apply to the before-string, the after-string, _and_ the display
>     property of the overlay.
>
> Can someone implement that?  It should not be fundamentally hard;
> making the properties apply is what is hard.
>
>     Note that there are additional problems.  One example (which I have
>     already reported) is that the face of the character in the buffer
>     after the overlay start location (which is not even in the overlay if
>     the overlay is of length zero) is applied to the before-string and
>     display properties of the overlay.
>
> 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.

>                                       Another example (which I think I
>     have not previously reported) is that the face of the character in the
>     buffer _after_ the overlay end location (which is _never_ in the
>     overlay) is applied to the after-string property.
>
> Let's consider that after this fix is done; perhaps this will
> solve that other problem as a byproduct.

I can't see any way that the change proposed here will help with that
problem.




By the way, changing topic to something else I mentioned in my earlier
message:  Johan Bockgård pointed out in another message that the
convenience functions font-lock-prepend-text-property and
font-lock-append-text-property already exist for the purpose of adding
faces to text (strings or buffer contents) that already have face
properties.  However, I have pointed out in a new bug report that
these functions don't work correctly for all possible face property
values (and indeed they sometimes raise errors).

-- 
Joe