Re: Unicode confusables and reordering characters considered harmful, a simple solution

[Eli Zaretskii]

> From: Yuri Khan <yuri.v.khan@gmail.com>
> Date: Thu, 4 Nov 2021 02:35:04 +0700
> Cc: Daniel Brooks <db48x@db48x.net>, Clément Pit-Claudel 
> <cpitclaudel@gmail.com>, 
>       Stefan Kangas <stefan@marxist.se>, Stefan Monnier 
> <monnier@iro.umontreal.ca>, 
>       Emacs developers <emacs-devel@gnu.org>
> 
> On Thu, 4 Nov 2021 at 02:09, Eli Zaretskii <eliz@gnu.org> wrote:
> 
> > Do you read Hebrew?
> 
> No. I just imagine how I’d perceive the text if I could.

IME, imagination doesn't help here.

> > > One does not only want to highlight, but also to actually see and
> > > distinguish certain characters
> >
> > What for?  The absolute majority of people won't have any idea what is
> > the effect of each of these controls, and how it differs from others.
> > Even I many times need to talk myself through their effect on display.
> > The UBA spec weighs in at more than 30 pages of highly technical text,
> > and I don't expect people to memorize it by heart.
> 
> Most people, when in the reader role, probably won’t and shouldn’t have to.
> 
> If I’m editing a text in a bidi language, though, I am expected to use
> format control characters

Actually, it is quite rare to need those controls.  Most people who
write RTL scripts every day don't even know those controls exist.

> and so I must know where they are or are not.

Then what we have in glyphless-char-display-control is better, and
doesn't need any changes, just customization of format-control to
display as acronyms.  Consider:

  . you get these characters stand out
  . they stand out, but in a somewhat subtle way, using a face that
    dims them
  . you clearly and unequivocally see which character is which -- no
    need to guess or remember what exactly does this or that arrow
    mean

> In the same vein, when I edit a program expected to conform to a
> coding style, I must know where spaces and tabs are, so I do not
> introduce whitespace-only changes or trailing blanks and keep
> indentation consistent. Or when I edit anything that will end up as a
> web page I want to know which spaces and hyphens are non-breaking, so
> the page will wrap correctly no matter how the user resizes their
> window and/or zooms the page. (No, I do not trust tools to do these
> things right; if they could, we would not need format control
> characters at all. I like tools to let me check what they did and
> correct if necessary.)

You seem to have some very unusual needs.  I find it hard to believe
that they are representative.