bug#54488: 29.0.50; move-to-column/overlay-related regression in latest master, perhaps 28?

[João Távora]

Eli Zaretskii <eliz@gnu.org> writes:

>> https://github.com/joaotavora/eglot/issues/125 (the one I gave you already) 
>> https://github.com/joaotavora/eglot/issues/124 (the bug that prompted the 
>> 125 fix)
>> https://github.com/joaotavora/eglot/issues/361 (an easier to grasp 
>> manifestation of the problem) 
>
> I see that you had problems reconciling the LSP idea of "columns" with
> that of Emacs.  If LSP indeed works in UTF-16 (I don't know, but I
> have no reason to doubt that), then I think your solution is decent,
> although actually encoding stuff could be overhead: after all, whether
> a given codepoint takes 1 or 2 UTF-16 code units can be easily
> established by looking at the codepoints themselves.  But that's an
> optimization.

An interesting one, though.  I think I follow.  Is there some easy way
in Emacs to measure how many UTF-16 code units a given codepoint takes?
I'm afraid I evicted this knowledge from the cache since I made that fix
2,5 years ago... Is a "codepoint" here a character in a string/buffer?

João