I want to disable Emacs from ever displaying text right-to-left (i.e. ignore Unicode control sequences to change text orientation). How to do it?
However, I also think that the Emacs maintainer (Eli) has recommended against setting variable
nil. I used to do that, but I switched to this (which I think Eli recommended at some point):
(setq-default bidi-paragraph-direction 'left-to-right)
You might try that instead. Since I've switched to doing this, and it seems to do the job - reduces or removes the (incredible) slowdown I experienced with buffers that display arbitrary Unicode chars. (I don't have a need to edit bidirectional text, but I provide some help commands that can display arbitrary Unicode chars - e.g. library Apropos Unicode (`apu.el).)
You might also want to pose your question to mailing list firstname.lastname@example.org. Eli and others who are experts on this might have better or more up-to-date recommendations or advice. (I'm no authority on bidi etc.)
Set the variable
Here's the docstring:
Documentation: Non-nil means reorder bidirectional text for display in the visual order. Setting this to nil is intended for use in debugging the display code. Don’t set to nil in normal sessions, as that is not supported. See also ‘bidi-paragraph-direction’; setting that non-nil might speed up redisplay.