Re: term, utf-8 and cooked mode, combining characters

[Niels Möller]

Marcus Brinkmann <Marcus.Brinkmann@ruhr-uni-bochum.de> writes:

> The other related question is about combining characters.  Should backspace
> delete the base character plus all combining characters, or only the last
> combining character?  This affects term and the console server.

I think the right answer depends on the input mechanism. Deleting base
char + combining characters sounds reasonable to me, but I think the
Right Thing is for backspace to undo the latest sequence of keystrokes
that makes (or is about to make) a visible difference to the user.

I.e. if I press my "ö" key and get "o" + combining diaeresis above
displayed on my screen, then I expect backspace to delete all of that
sequence. But if I pressed the "o" key to get an o and then pressed
some "add-dots" key to make it an ö, then I'd expect backspace to only
delete the dots. And then we have the common dead key input mechanism,
I'd expect that dead-diaeresis + "o" + backspace deletes an ö, and
that dead-diaeresis + backspace + o results in a plain o (that seems
to be the way X input behaves).

I'm afraid it's hard to get backspace to do the Right Thing in all
cases without some cooperation with the input driver, but my picture
of how all these servers fit together is too blurry for me to see if
that cooperation is practical.

Regards,
/Niels