Re: bidi and shaping problems in describe-input-method

[Mohsen BANAN <list-general@mohsen.1.banan.byname.net>]

>>>>> On Wed, 07 Mar 2012 06:05:19 +0200, Eli Zaretskii <eliz@gnu.org> said:
  >> From: Mohsen BANAN <list-general@mohsen.1.banan.byname.net>

  Mohsen> In the case of 'arabic note how the entire
  Mohsen> keyboard is flipped to the right.

  Eli> That's easy to fix.

Great! Thanks for having taken care of that.

  Mohsen> The second problem is shaping related:
  Mohsen> 
  Mohsen> Inside of a cell on the keyboard layout, when
  Mohsen> there are two characters that can be joined, they
  Mohsen> are joined -- be default. They should not be.

  Eli> How can one know when they should be joined and when not?

I think the simple answer is: always isolated -- never joined.

For Persian and Arabic I am sure that they should
never be joined -- always isolated. 

For other shaped languages, it is hard to imagine
an input method designer would ever want them joined.

For non-shaped languages (e.g., latin keyboards)
the insertion of an zero width non-joiner between
lower and upper case is harmless and invisible.

So, the simplest fix (and perhaps
the-right-thing-to-do) is to ALWAYS insert a
(ucs-insert 8204)‌ -- zero width non-joiner --
between the two characters in each and every
keyboard cell.

Thanks,

...Mohsen