Re: How to recognize keyboard insertion?

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sat, 31 Oct 2009 17:37:07 +0000
> From: David De La Harpe Golden <david@harpegolden.net>
> CC: emacs-devel@gnu.org
> 
> > To simplify, this means that a `(' should be mirrored when surrounded
> > by strong R2L characters, but not when surrounded by Latin characters
> > or European digits.
> > 
> 
> It IS only mirrored when surrounded by rtl characters, that was
> what I included the nonsense string for.  When not so surrounded,
> it, Shift-9 generates ")" /and it is shown as ")"/.

My understanding is that Shift-9 generates `(' or `)' depending on
whether the current keyboard is Latin or Arabic, not depending on the
characters surrounding the parenthesis.  All your examples show that
(and I see the same on my Windows box if I switch the keyboard to
Hebrew).  Do you agree?

> > For example, try typing "9*(4+5)" after switching to Arabic keyboard.
> > What do you get?
> >
> 
> 
> 9*)4+5(

Which is wrong, don't you think?

> surrounded:
> 
> ثثث9*)4+5(ثثث
> - but that was when I typed the expression as if LtR (i.e. hitting 9 
> first)

This is how digits and other mathematical expressions are typed in
bidirectional text.

> I suspect an arabic person might type
> 
> ثثث(5+4)*9ثثث
> 
> - i.e. hitting ")" first when transcribing "9*(4+5)".

Maybe if the digits are Arabic digits.  I don't know enough Arabic to
judge this example.  Hebrew uses European digits, and they are typed
left to right, exactly like in Latin scripts.  We could, of course,
tell users to switch off Hebrew input method when typing math, but
that's an annoyance, IMO.

> > Quail cannot easily know the context: it can only mirror these
> > characters always, which is not right, since the display will mirror
> > them only if they are surrounded by strong R2L characters.
> 
> I expect that's in fact what arabic users expect, though an actual 
> arabic person might want to speak up...

Maybe, I really don't know.