Bidi paragraph direction in terminal emulators (was: Proposal for BiDi in terminal emulators)

Eli Zaretskii via Unicode unicode at
Fri Feb 8 15:36:17 CST 2019

> From: Egmont Koblinger <egmont at>
> Date: Fri, 8 Feb 2019 17:44:53 +0100
> Cc: Richard Wordingham <richard.wordingham at>, 
> 	unicode Unicode Discussion <unicode at>
> For certain apps, one of the modes is required (e.g. for cat it's the
> implicit mode). For other tasks it's the other mode (e.g. for emacs
> the explicit mode).

No one in their right minds will run Emacs inside the Emacs terminal
emulator.  And even for other applications, disabling bidi will almost
always needed only for full-screen programs, which use curses-like
libraries to address the entire screen.  So you'd switch off
reordering for the entire time you are running such an app, then
switch it back on after exiting.

The other, simpler text applications will always need reordering to

> > You can hardly expect Emacs (or any other application) to support
> > control sequences that are not yet defined, let alone standardized.
> The most essential sequence, BDSM to switch between implicit and
> explicit modes, has been defined for like 28 years now. Sure I bring
> slight changes and clarifications to it, as well as introduce new
> ones. As of my recommendation which I've announced, these new ones are
> defined as well.

Are there any terminal emulators that support these sequences?

> > When they become sufficiently widely available, I'm sure someone will
> > add them to Emacs.
> There's always a chicken and egg problem with this attutide. At the
> very least, I'm kindly asking Emacs to emit BDSM so that when it's
> fired up on a gnome-terminal, it'll have the terminal's BiDi
> automatically disabled.

Feel free to file a feature request with the Emacs bug tracker about
this.  Somebody, maybe even myself, is likely to act on that at some

More information about the Unicode mailing list