On Wed, 4 May 2022 at 10:23, Eli Zaretskii wrote: > > Date: Wed, 04 May 2022 09:20:05 +0200 > > From: frederik.fouvry--- via "Bug reports for GNU Emacs, > > the Swiss army knife of text editors" > > > > > > I forgot to add: > > > > The Unicode noncharacters should not cause a change in writing > > direction, since they are not Arabic characters, but a set of characters > > for internal use only (no exchange between different parties). > > That is not entirely true, because Unicode assigns default Bidi Class > properties to some unassigned codepoints, and Emacs obeys that. So an > unassigned codepoint (which is AFAIU what "noncharacter" stands for in > your terminology) for which Unicode says that its Bidi Class should > be, for example, AL, _will_ cause change of text directionality. > > If you use those unassigned codepoints for private use, you will have > to override the default properties by manually modifying the relevant > Emacs char-tables at run time. > That sounds fair enough. I admit that my statement was generalising too much. The odd name "noncharacter" is Unicode terminology, not mine (see e.g. Spec v14, Ch. 2, p.30).