Re: 22.2.50; Display of "zero width no-break space" (U+FEFF)

[Chong Yidong <cyd@stupidchicken.com>]

Juri Linkov <juri@jurta.org> writes:

>>>> This is the same character as BOM.  But since it is *ZERO-WIDTH*
>>>> NO-BREAK SPACE, it seems it shouldn't be displayed at all in view mode.
>>>> But it edit mode, it would be preferable to have some indication
>>>> about the presence of this character in the buffer.
>>
>> If "view mode" is meant to be more general than the minor mode
>> `view-mode', I agree.  E.g. in Gnus article buffer (a read-only buffer
>> where articles are displayed), `nobreak-char-display' is set to nil
>> whereas when composing or replying, Emacs' default is used.
>
> We definitely should highlight ZERO-WIDTH NO-BREAK SPACE in
> whitespace-mode, but for editing modes I'm not so sure.

By default, Emacs should highlight ZERO-WIDTH NO-BREAK SPACE.  If
individual major modes, like Gnus buffers, want to hide this character,
that's up to them; we don't have to worry about it.  It's just like how
Emacs ordinarily displays page breaks as ^L, whereas the Gnus article
buffer has special code to split articles into pages.