Re: Unicode 4.01 bidi type changes

On Tue, 27 Apr 2004, Beni Cherniavsky wrote:
> Eran Tromer wrote:
>
> Diff gives the following list of bidi category changes.  I give examples
> of affected texts and/or comments where I have ones.
>
> {PLUS SIGN,HYPHEN-MINUS}: ET -> ES
>      :Logical:    HEBREW-10
>      :Old visual: -10WERBEH
>      :New visual: 10-WERBEH
>
>      At last!  The old behavior confused so many users!  However this
>      also breaks stand-alone numbers:
>
>      :Logical:    HEBREW -10
>      :Old visual: -10 WERBEH
>      :New visual: 10- WERBEH
>
>      ?!? How are we to write signed numbers in RTL text now?!?  LRM?
>      Also ugly...  I'm not sure it's a good idea.  And I can't see the
>      rationale for PLUS SIGN at all.

Ok, lets move to the U+2212 MINUS SIGN then :).

>      This is a **really big change**.  I suppose every third big RTL
>      text out there will be affected.

Unfortunately you are right.  And worse is that it takes a
century for all software around to be updated.  Hopefully Pango
will incorporate this in the next release, but don't ask about
KDE, Mozilla, OO.o, blah blah...

> SOLIDUS: ES -> CS
>      :Logical:    ARABIC 27/4
>      :Old visual: 4/27 CIBARA
>      :New visual: 27/4 CIBARA
>
>      Don't know how much this makes sense - can any Arabic speaker
>      comment?

I don't know either :).  Guess it's better now.  But not sure if
it worth the change.

> SOFT HYPHEN: ON -> BN
>      It is now OK to position it anywhere or omit it altogether?
>      Don't ask me why...

Yes.  Good change, as it's really a Boundary Neutral.

> FRACTION SLASH: ON -> CS
>      :Logical:    RTL 3/4  (The ``/`` being a FRACTION SLASH)
>      :Old visual: 4/3 LTR
>      :New visual: 3/4 LTR
>
>      Makes perfect sense.  If SOLIDUS was a number separator, FRACTION
>      SLASH surely deserves to be.

Definitely.

> CIRCLED {DIGIT ZERO,...,NUMBER TWENTY}: EN -> ON
> PARENTHESIZED {DIGIT ONE,..., NUMBER TWENTY}: EN -> ON
>      Since they are circled/parenthesized, putting several together
>      doesn't mean constructing a number from them - (1)(2) is hardly
>      twelve :-) - so they shouldn't order LTR.  Makes sense.  Besides,
>      nobody cares for these chars anyway ;-).

Exactly :D.

> BRAILE PATTERN {BLANK,DOTS-*}: ON -> L
>      Makes sense for English readers but what if the Braile patterns
>      represent Hebrew text?  Or is Braile written LTR in all languages?
>      Can anyone shed a light?

In Persian they use Braile LTR.  Guess there's no RTL Braile.
Omer?

> INTERLINEAR ANNOTATION {ANCHOR,SEPARATOR,TERMINATOR}: BN -> ON
>      Yep, annotations' position is meaningful, I suppose.

Don't know exactly what they are supposed to do.  But yes, makes
sense.

--behdad
  behdad.org