Problems with BidiCharTest.txt
Eli Zaretskii via Unicode
unicode at unicode.org
Sun Jul 16 12:09:19 CDT 2017
> Date: Sun, 16 Jul 2017 07:13:02 +0300
> From: Dov Grobgeld via Unicode <unicode at unicode.org>
> While implementing UAX#9 for Unicode 6.3 (and beyond) in FriBidi, I'm trying to pass all the tests of
> BidiCharacterTest.txt , and I'm having problem understanding a few of the tests that to me appear to
> contradict the spefication. The problematic lines in BidiCharacterTest-10.0.0.txt are the tests on lines 262,
> 263, and 264.
> Let's consider test from line 262:
(I believe you meant line 264.)
> Dir: RTL
> Input: a ( b <RLE> c <pdf> ) _ 1
> Level: 2 2 2 x 4 x 1 1 2
> The problem I'm having is that the first opening bracket is assigned level 2 and the closing bracket level 1.
> This seems to contradict the three rules N0.b, N0.c.1, and N0.c.2 in the specification that all describe
> overriding the type of both brackets with either the embedding or the opposite direction. The only case we can
> possibly get different levels (correct me if I'm wrong!) is if rule N0.d is applied and the brackets retain their
> neutral status until they are resolved in subsequent rules.
The example is correct, IMO. (FWIW, Emacs produces the same reordered
display as expected by the test.) I think the effect you mention is
produced by the RLE..PDF embedding: it causes the opening and the
closing parentheses to be in 2 different isolating run sequences, see
examples in BD13. Bracket pairs are processed as such only if they
are in the same isolating run sequence. Try the same test without the
RLE..PDF part, and you will see the result you expect.
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