Re: manipulating (capitalize, lower case) unicode bold and italic characters

[Eli Zaretskii <eliz@gnu.org>]

> From: Marcin Borkowski <mbork@mbork.pl>
> Cc: help-gnu-emacs@gnu.org
> Date: Mon, 08 Jul 2019 15:11:44 +0200
> 
> > I don't understand what you mean by "fraktur", though.
> 
> https://en.wikipedia.org/wiki/Fraktur

Thanks, I know what Fraktur is, I just don't understand what it has to
do with the issue at hand.  There's no "fraktur" block in Unicode,
AFAIK.

> >> It would also be good to be able to change case easily (and i guess
> >> this should work whether the characters are greek or latin, and work
> >> with arabic digits as well).
> >
> > This already does work with any character for which Unicode defines
> > the upper-case or lower-case pair.  Use M-l and M-u.
> 
> A quick test shows that this won't work in the current state of affairs.

??? Where doesn't it work, and why?