Re: How to recognize keyboard insertion?

[David De La Harpe Golden <david@harpegolden.net>]

Eli Zaretskii wrote:


> 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?


Probably - Shift-9 generates  parenleft (#x28) or parenright (#x29) 
depending on current keyboard layout. #x28 is then displayed as ( in ltr 
context, or ) in rtl context.


> 
>>> 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?
>

It's clearly not a valid arithmetical expression... It is however how 
mature bidi capable apps I tried behave, for better or worse. I don't 
think this is an area where emacs, bidi latecomer, should diverge from 
established practice, especially not by default - rtl-native users 
presumably by now expect to press the key labelled ")" to get "(" when 
using their native keymap but in an ltr context. Maybe they regard that
as an annoyance, I dunno, or maybe it's a semantic-map feature, since 
the same shift-0 keypress still makes an opening paren (modern hebrew 
text, at least, seems to sometimes use () in text, not just arithmetic 
much like english, at least judging by wikipedia hebrew texts).

But therefore it's not necessary to track whether the character was 
entered by keyboard unless you want to provide a further unusual "smart"
layer that doesn't work like typical bidi apps.

>> 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. 

Note that western "arabic numerals" vs. eastern arabic numerals is 
apparently a matter of font+bidi display (again for better or worse)  - 
i.e. if I then copy just the expression above from within the rtl string 
and paste it into a ltr context, I get:

(5+4)*9