Re: minor mode for highlighting character classes such as non-ascii (bug 47455)

[Daniel Martín]

"Roland Winkler" <winkler@gnu.org> writes:

> In the context of bug 47455 the idea emerged that it can be useful
> to have a minor mode that highlights non-ascii characters.  I want
> to ask hear for feedback: does such a mode already exist?  Can it be
> useful to have this minor mode more general such that the highlighted
> character classes become configurable?  Are there possible use cases
> for this beyond non-ascii characters?

There's already a feature in the display engine that shows certain
non-ASCII characters with a special face.  For example, U+00A0 (no-break
space) is shown with the ‘nobreak-space’ face, U+00AD (soft hyphen),
‘U+2010’ (hyphen), and ‘U+2011’ (non-breaking hyphen) are shown with the
‘nobreak-hyphen’ face.  Perhaps your suggestion could be a
backwards-compatible extension to this hardcoded display mechanism.

Another option is to simply instruct users to use Hi Lock mode with
"[^[:ascii:]]".