Unclear text in the UBA (UAX#9) of Unicode 6.3
eliz at gnu.org
Tue Apr 22 12:02:18 CDT 2014
> Date: Tue, 22 Apr 2014 09:06:27 -0700
> From: Asmus Freytag <asmusf at ix.netcom.com>
> CC: Eli Zaretskii <eliz at gnu.org>, ken at unicode.org,
> unicode Unicode Discussion <unicode at unicode.org>,
> James Clark <jjc at jclark.com>
> I believe that your scheme does not match the PBA in that it assumes
> that brackets are hierarchical and attempts to preserve the best
> hierarchy, whereas PBA assumes that pairs that are closer together are
> more likely to be correct matches (for non-mathematical texts
> hierarchies are not the norm (and they are shallow at best)).
Indeed, that's the somewhat counter-intuitive part of the PBA, one
that IMO should be explicitly pointed out in the text (as a note),
because many readers will not expect that.
> D 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.
> R Characters are resolved into resolved bracket pairs as follows:
> Starting at the beginning of the text, when the a closing bracket
> is encountered, find the nearest preceding opening character that is
> not part
> of a resolved pair, and not ignored for pair resolution and that can
> form a
> bracket pair. If one exists, resolve the pair, and mark any enclosed
> brackets of any kind as ignored. Otherwise, if no pair can be
> resolved, mark
> the closing bracket as ignored.
Please compare this with my latest suggestion. I think I say the same
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