Unclear text in the UBA (UAX#9) of Unicode 6.3

Eli Zaretskii eliz at gnu.org
Tue Apr 22 12:11:34 CDT 2014

> Date: Tue, 22 Apr 2014 09:52:43 -0700
> From: Asmus Freytag <asmusf at ix.netcom.com>
> CC: nospam-abuse at ilyaz.org, verdy_p at wanadoo.fr, ken at unicode.org, 
>  jjc at jclark.com, unicode at unicode.org
> > I agree, but let me try to say the same more concisely:
> >
> >     A bracket pair is a pair of an opening paired bracket and a closing
> >     paired bracket characters within the same isolating run sequence,
> >     such that the Bidi_Paired_Bracket property value of the former
> >     character or its canonical equivalent equals the latter character
> >     or its canonical equivalent, and provided that a closing bracket is
> >     matched to the closest match candidate, disregarding any candidates
> >     that either already have a closer match, or are enclosed in a
> >     matched pair of other 2 bracket characters.
> >
> >
> I think that this (or something like this) might work, but that we are 
> better off
> splitting this into a definition and a rule as I have proposed in my 
> previous message.

Why not have the above _and_ a rule?  The rule should be worded so as
to help understanding the definition.  But IMO it is not a good idea
to have a rule as an integral part of the definition, because the two
serve different purposes.

And I think we should also point out explicitly that the brackets
match non-hierarchically, as many readers will expect that they are,
and will be confused.

> In the rest of the bidi algorithm, rules are used to describe actions
> taken on scanning text, and "resolving" bracket pairs is such a scan.

Yes, but other definitions don't use rules as their integral parts.
Why should this one be an exception?

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