Re: bidi-display-reordering is now non-nil by default

[Stefan Monnier]

> Btw, I've looked at all the users of (space :SOMETHING) spec in
> Emacs.  Almost all of them use :align-to.  The rest all use :width,
> and with a single exception (ruler-mode, which uses this on the
> fringes, and so is irrelevant to this discussion), all of them use
> this to separate and align fields.

Thanks for looking at it.  It confirms my impression.

>> Maybe all `space' display properties should be treated as field
>> separators, but with a new :not-a-bidi-field-separator property
>> that can override this default.
> If we want to keep this simple enough to get into 24.1, I suggest to
> treat them all as segment separators, and not introduce any overriding
> properties until someone comes with a convincing use case that
> actually needs something like that.

OK.

>> For Emacs-24, I've made an effort to try and reduce the amount of
>> alternative completion code (most of which was not like
>> ido/iswitchb/.. but more like lisp-mode or makefile-mode
>> re-implementing the simple completion code already implemented for the
>> minibuffer), so I guess that nowadays there's mostly just ido and iswitchb
>> bundled with Emacs plus company-mode in the GNU ELPA (hopefully soon
>> accompanied with auto-complete and completion-ui).

> Thanks, I will take a look.

iswitchb already uses display-completion-list when displaying
completions in *Completions*.  And ido.el never displays anything in
*Completions*, AFAICT.
But both of them (along with icomplete.el) show a list of completions
"inline" in the minibuffer as in

  Switch to buffer: a{data.tex,foo.ada,*scratch*}

so maybe the {,,,} list should use bidi-string-mark-left-to-right before
the comma.  BTW, I think we should make it clear that
bidi-string-mark-left-to-right only makes sense in text that gets
displayed in L2R paragraphs, so it's largely restricted to buffers that
should set bidi-paragraph-direction to `left-to-right'.

> Need your decision on the space spec.

Is the above enough, or are there still more open issues?


        Stefan