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

[Dan Hitt]

On Mon, Jul 8, 2019 at 6:51 AM Eli Zaretskii <eliz@gnu.org> wrote:

> > From: Marcin Borkowski <mbork@mbork.pl>
> > Cc: help-gnu-emacs@gnu.org
> > Date: Mon, 08 Jul 2019 15:11:44 +0200
> >
> ......
>
> > >> 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?
>

Thanks Eli, Marcin, and Stefan for your help.

Here's an example of what doesn't work, i think.

If you enter a mathematical italic small w (0x1D464) and a mathematical
italic capital w (0x1D44A) and do 'describe-char' for each, the small one
has the Lowercase general category, while the capital has the Uppercase
general category.  I did not know about the concept of 'case pair' in
unicode, so i guess it is possible that even though emacs knows one is
Lowercase and one is Uppercase, it is possible that it does not know that
they are in a pair.  (How would i find out, from emacs?)  The commands
downcase-region and upcase-region do not work on them, at least for me
(emacs 24.5.1, on debian 9).  (I guess what i'd want to do in that case is
keep some kind of file in .emacs.d that defines custom case-pairs.  ??)

Regarding markdown, i do like markdown, and i'm glad there's a markdown
mode.  However, for commenting code, i'm not sure how it would fit in: the
code file would have to be in two modes?  And also, even though i might be
able to convince emacs to recognize the markdown, cat would not, nor would
vi or other programs.   (I don't want to be too inauthentic here, because
normally i don't use vi for anything, but i did read some sample files with
vi, and it can pick up the unicode stuff without missing a beat.  Likewise
cat and more also have no issue with it, at least using the xfce4-terminal
in debian.)

Thanks again everybody for your help, and for educating me about case pairs
in unicode!!

dan