bug#3568: 23.0.94; no doc for character composition

[Drew Adams <drew.adams@oracle.com>]

> > 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.

I'd like an explanation of character composition, in the Elisp manual.
If you don't want to add one, or you don't think it is useful for users,
so be it.

As one user, I know nothing about this.  And I still know nothing
about it after reading that doc string.  FWIW.