Re: describe-char on emoji sequences

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: emacs-devel@gnu.org
> Date: Wed, 27 Oct 2021 16:25:49 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> Take ⚠️:
> 
>              to input: type "C-x 8 RET 26a0" or "C-x 8 RET WARNING SIGN"
>           buffer code: #xE2 #x9A #xA0
>             file code: #xE2 #x9A #xA0 (encoded by coding system utf-8-emacs)
>               display: composed to form "⚠️" (see below)
> 
> Composed with the following character(s) "️" using this font:
>   ftcrhb:-GOOG-Noto Color Emoji-medium-normal-normal-*-19-*-*-*-m-0-iso10646-1
> by these glyphs:
>   [0 1 9888 112 24 0 24 18 5 nil]
> with these character(s):
>   ️ (#xfe0f) VARIATION SELECTOR-16
> 
> If you insert
> 
> C-x 8 RET WARNING SIGN and then C-x 8 RET VARIATION SELECTOR-16 you
> indeed get:
> 
> ⚠️
> 
> So 
> 
>              to input: type "C-x 8 RET 26a0" or "C-x 8 RET WARNING SIGN"
> 
> could just be expanded to include all the code points in the
> decomposition.  Of course, with some of these sequences (with five code
> points), doing this is completely impractical, so perhaps it's not worth
> doing. 

We could add such a feature, but note that the existing display all
but gives it to you already: it shows the codepoints of the other
characters in parentheses.

> The point of this is that it's not always clear what an emoji is trying
> to express.  For instance, if somebody writes you a message about 👨🏻‍✈️,
> it'd be nice if Emacs could tell you that it's a "man pilot".

Here, you are talking about a different feature: a kind of "parser" of
Emoji sequences that would convert a sequence of characters into its
Emoji description.  I don't think it belongs to describe-char, but it
could be a useful feature on its own.