Annoyances from Implementation of Canonical Equivalence (was: Pure Regular Expression Engines and Literal Clusters)

[Richard Wordingham via Unicode]

On Tue, 15 Oct 2019 09:43:23 +0300
Eli Zaretskii via Unicode <unicode at unicode.org> wrote:

> > Date: Tue, 15 Oct 2019 00:23:59 +0100
> > From: Richard Wordingham via Unicode <unicode at unicode.org>
> >   
> > > I'm well aware of the official position.  However, when we
> > > attempted to implement it unconditionally in Emacs, some people
> > > objected, and brought up good reasons.  You can, of course, elect
> > > to disregard this experience, and instead learn it from your
> > > own.  
> > 
> > Is there a good record of these complaints anywhere?  
> 
> You could look up these discussions:
> 
>   https://lists.gnu.org/archive/html/emacs-devel/2016-02/msg00189.html
>   https://lists.gnu.org/archive/html/emacs-devel/2016-02/msg00506.html

These are complaints about primary-level searches, not canonical
equivalence.

> > (It would occasionally be useful to have an easily issued command
> > like 'delete preceding NFD codepoint'.)  
> 
> I agree.  Emacs commands that delete characters backward (usually
> invoked by the Backspace key) do that automatically, if the text
> before cursor was produced by composing several codepoints.

That's pretty standard, though it looks as though GTK has chosen to
reject the principle that backwards deletion deletes the last character
entered.

> Sure.  There's an Emacs command (C-u C-x =) which shows that
> information for the text at a given position.

Or commands what-cursor-position and describe-char if an emulator
gets in the way.  Having forward-char-intrusive would make it perfect.

Richard,