bug#32599: 25.2; Feature request: input PUA characters by name

[Eli Zaretskii <eliz@gnu.org>]

> From: jsbien@mimuw.edu.pl (Janusz S. Bień)
> Cc: 32599@debbugs.gnu.org
> Date: Sun, 26 May 2019 17:18:21 +0200
> 
> > In addition, I think PUA codepoints aren't really treated as
> > characters in Emacs, so there's a need for some infrastructure
> > changes.
> 
> I do not propose to support the supplemental PUA planes. For the BMP
> this probably boils down to the availability of the property
> information. As we have now a pseudo-UnicodeData.txt for the PUA
> characters (at least thise I'm interested in) this doesn't seem to me a
> big problem).

I think we are miscommunicating.  The problems I alluded to start from
the fact that we exclude the PUA codepoints from the character
property database.  This means you cannot change their case and access
their syntax category, for example.  Functions that select a suitable
font also ignore PUA codepoints, IIRC.  Etc. etc. -- Someone™ should
go over all the places where we specify character properties and use
them, and make sure PUA codepoints aren't disregarded.  Otherwise,
just making Emacs know the names of these codepoints will be of very
limited value.