RE: BIDI : tackling the delimiter weirdness

> I think the IRI draft should state that schema definitions MUST define
> their delimiters relationships and directionality. That would solve
> the problem.

Right now, the IRI draft suggests changes to RFC 4397; I think
our charter calls for updating RFC 3397 separately.

I'm not sure how having IRI schemes define delimiter relationships
and directionality helps.   While some applications of HTTP

http://ab.cd/ef/gh/ij.html


are "hierarchical" in some way, others aren't. And there really isn't
an opportunity to restrict IRIs to what is or isn't "allowed".

You might want to define consistent presentational guidelines, 
but having them implementable uniformly and also be maximally
usable are likely requirements at odds.

Again, I would like to move the guidelines on presentation
into a separate document so that it can progress independently;
I don't think there is a two-way dependency.

Larry



section 4.4.  Examples
> (...)
>   Example 5: Example 2, applied to components of different kinds:
>   Logical representation: "http://ab.cd.EF/GH/ij/kl.html"
>   Visual representation: "http://ab.cd.HG/FE/ij/kl.html"
>   The inversion of the domain name label and the path component may be
>   unexpected, but it is consistent with other bidi behavior.  For
>   reassurance that the domain component really is "ab.cd.EF", it may be
>   helpful to read aloud the visual representation following the bidi
>   algorithm.  After "http://ab.cd." one reads the RTL block
>   "E-F-slash-G-H", which corresponds to the logical representation.
>
>   Example 6: Same as Example 5, with more rtl components:
>   Logical representation: "http://ab.CD.EF/GH/IJ/kl.html"
>   Visual representation: "http://ab.JI/HG/FE.DC/kl.html"
>   The inversion of the domain name labels and the path components may
>   be easier to identify because the delimiters also move.
>
>   Example 7: A single rtl component includes digits:
>   Logical representation: "http://ab.CDE123FGH.ij/kl/mn/op.html"
>   Visual representation: "http://ab.HGF123EDC.ij/kl/mn/op.html"
>   Numbers are written ltr in all cases but are treated as an additional
>   embedding inside a run of rtl characters.  This is completely
>   consistent with usual bidirectional text.
>
>   Example 8 (not allowed): Numbers are at the start or end of an rtl
>   component:
>   Logical representation: "http://ab.cd.ef/GH1/2IJ/KL.html"
>   Visual representation: "http://ab.cd.ef/LK/JI1/2HG.html"
>   The sequence "1/2" is interpreted by the bidi algorithm as a
>   fraction, fragmenting the components and leading to confusion.  There
>   are other characters that are interpreted in a special way close to
>   numbers; in particular, "+", "-", "#", "$", "%", ",", ".", and ":".
>
>   Example 9 (not allowed): The numbers in the previous example are
>   percent-encoded:
>   Logical representation: "http://ab.cd.ef/GH%31/%32IJ/KL.html",
>   Visual representation: "http://ab.cd.ef/LK/JI%32/%31HG.html"
>
>   Example 10 (allowed but not recommended):
>   Logical representation: "http://ab.CDEFGH.123/kl/mn/op.html"
>   Visual representation: "http://ab.123.HGFEDC/kl/mn/op.html"
>   Components consisting of only numbers are allowed (it would be rather
>   difficult to prohibit them), but these may interact with adjacent RTL
>   components in ways that are not easy to predict.
>
>   Example 11 (allowed but not recommended):
>   Logical representation: "http://ab.CDEFGH.123ij/kl/mn/op.html"
>   Visual representation: "http://ab.123.HGFEDCij/kl/mn/op.html"
>   Components consisting of numbers and left-to-right characters are
>   allowed, but these may interact with adjacent RTL components in ways
>   that are not easy to predict.


--
Slim Amamou | سليم عمامو
http://alixsys.com

Received on Thursday, 28 January 2010 06:19:18 UTC