Re: Nested display strings

[Eli Zaretskii]

> From: "Drew Adams" <address@hidden>
> Cc: <address@hidden>
> Date: Sat, 23 Apr 2011 16:20:04 -0700
> 
> > But what to do in the case I presented, where one of the overlays
> > covers only a subset of positions covered by the other?  
> 
> At any given position there is one overlay or two.

Unlike most other properties, the `display' property does not affect
each character separately.  It replaces them all as a single unit.  So
asking about "any given position" is meaningless in this case.  As you
say, having the properties alternate back and forth on adjacent
characters would produce nonsensical display, if we were to interpret
the feature that way.

> If a higher-priority overlay is strictly nested within a lower-priority one,
> then I would naively expect the lower one to win outside the overlap and the
> higher one to win inside it.
> 
> If the higher-priority overlay is the wider one, then I would expect the
> lower-priority one never to show.

This is how it works now, but I don't think it makes much sense to
show a display string more than once.  I think this should work as in
the latter case (i.e. the "narrower" overlay is never seen),
regardless of the priorities.