bug#3568: 23.0.94; no doc for character composition

[Eli Zaretskii <eliz@gnu.org>]

> Date: Wed, 27 Apr 2016 12:42:56 -0700 (PDT)
> From: Drew Adams <drew.adams@oracle.com>
> Cc: 3568@debbugs.gnu.org
> 
> No.  `compose-region' already had that doc string when the bug was
> reported.  That doc string has been around since at least Emacs 22.

Then I don't understand what else do you want to know about
compose-region and character composition in general.

> I would expect some conceptual explanation of character composition
> in the Elisp manual.

Please start by explaining what is missing from the doc string of
compose-region, because otherwise it is impossible to translate your
expectation to any concrete text.

The example you gave in the bug report is not about character
composition, it's about font-lock.  So maybe that is what you need to
be explained.  However, the bug report says "character composition",
so until you agree it's about something else, "character composition"
it is.

> Including how to decompose composed chars etc.

You can't.  This question makes no sense.  Character composition
converts several characters into one or more glyphs to be displayed;
you cannot "decompose" them, and in any case the result of such
decomposition is known in advance: they are the original characters.

> What the bug report mentions.  I don't think that a doc string for
> one command covers this topic.

Well, I think it does.  You could change my mind by telling what is it
that you miss in that doc string.