Re: Better emoji support

[Eli Zaretskii]

> From: Robert Pluim <rpluim@gmail.com>
> Cc: kevin.legouguec@gmail.com,  emacs-devel@gnu.org
> Date: Mon, 20 Sep 2021 19:32:23 +0200
> 
>     Eli> My idea is to trick the font_range function, which verifies that the
>     Eli> sequence can be composed using a single font, to use an Emoji font
>     Eli> when it sees something followed by a variation selector, instead of
>     Eli> the font for the first character in the sequence.  For that, the 
> rules
>     Eli> for Emoji sequences in composition-function-table should be anchored
>     Eli> on the VS-n codepoints (which I think is a good idea regardless).
> 
> Weʼd have to raise the lookback limit for composition-function-table
> rules higher than 3 (maybe only to 4).

Examples?  Not that it's a catastrophe.

> I guess it reduces the number of entries in
> composition-function-table, but then you end up with a lot of rules
> for eg VS-16.

Why do you think we need to have a lot of such rules?  What kind of
rules did you think about?

> emoji-zwj-sequences.txt would result in about 840 rules,
> with a lot of redundancy, which could be reduced, but I think that can
> wait until after the zwj sequence stuff goes in.

I guess I'm missing something because I don't see a problem there.