bug#28339: 25.2; Emacs shows ZWNJ character (Zero Width non-Joiner) as Space

[handa <handa@gnu.org>]

In article <83h8w0hwa7.fsf@gnu.org>, Eli Zaretskii <eliz@gnu.org> writes:

> I don't see this in Unicode, but maybe I'm missing something.

> Anyway, what would you suggest as a solution to this issue?  Should we
> install the arabic-font-shape-gstring function into Emacs?  Do we need
> to do something else in addition?  E.g., do we need to make the
> display of ZWNJ optional?

As I don't know what is the right thing, I'm asking here.

If users never ever want to put cursor on ZWNJ,
arabic-font-shape-gstring-ZWNJ-absorb is the solution.

If users want a thin space to be able to handle ZWNJ directly,
arabic-font-shape-gstring-ZWNJ-as-space is the solution.

If it depends on a situation or a user's prefernce, it is better to have
a user customizable variable to switch between them.

By the way, I've just tried arabic-shape.el on Windows, and found that
arabic-font-shape-gstring-ZWNJ-as-space worked, which means Windows text
laout backend on Windows (uniscribe?) also returns ZWNJ glyph.  And,
without arabic-font-shape-gstring-ZWNJ-as-space, I see a strange cursor
display.  Is it the "glitch" you mentioned?

---
K. Handa
handa@gnu.org