Re: Unicode confusables and reordering characters considered harmful, a simple solution

[Juri Linkov]

>>> Anyway, if one wants to be able to highlight certain characters on
>>> display, one could also use highlight-regexp, I think.
>>
>> Or markchars.el with markchars-what customized to markchars-confusables.
>
> Neither would work AFAICS, because these characters are
> glyphless. Highlighting a glyphless character will not make it more
> visible.

Eli pointed out that instead of highlighting glyphless characters,
only suspicious text between glyphless characters should be highlighted:

  For example, when a character with a strong left-to-right directionality
  has its directionality overridden to behave like right-to-left
  character, that is highly suspicious, because it makes no sense to do
  that in 99.99% of valid use cases.

markchars.el has a rule that highlights adjacent characters from
different scripts, so a new rule could be added that will highlight
text that has no right-to-left characters between directionality
switching characters.