Re: [xml-dev] Your XML documents may use different sets of characters,de

[David Carlisle <davidc@nag.co.uk>]

On 17/05/2011 14:45, Costello, Roger L. wrote:
> Hi David,
>
> So, you are saying that the "data" that I use in an XML document (as
> opposed to the "markup") can be anything that has a decimal or
> hexadecimal value, e.g.,
>
> ￞
>

everything except unpaired surrogate codepoints and a few control
characters: you can't do  in xml 1.0 (you can in xml 1.1 though)
the exact lists are in the spec, but the lists don't depend on unicode
versions.


> Suppose that I require,
>
> The value (i.e., "data") of the<foo>  element is zero or more
> characters from the Unicode Nd category.

that's an XSD question (I assume) not an XML one.

If you specify Nd you mean any decimal, that set will get larger
potentially as more scripts are added, which in any case where you want
"any decimal in any script" is probably a good thing. If you meant 0-9
it's better to use [0-9].

>
> What characters must be used in the<foo>  element?
>
>> From what you are saying, it depends entirely on the implementer.
>> If the implementer implements Unicode 2.0 then Nd may consist of
>> 600 characters. If the implementer implements Unicode 2.1 then Nd
>> may consist of 610 characters. And this is the case whether I'm
>> using XSLT, XML Schema, RELAX NG, etc. Right?
>

yes but I don't see an issue with it particularly or any way to avoid 
that kind of thing other than tell people they can not use their native 
language scripts even after those scripts have been added to Unicode
(which was essentially what xml 1.0 pre 5th edn did for element names).
That might have been acceptable for element names and other syntactic 
constructs but is never going to be acceptable for character data.

If you are writing a regexp pattern and need to worry about this then 
it's always possible to use explicit character ranges rather than using 
the named unicode categories. The main reason for using the categories 
is that they _do_ expand in culturally sensible ways as Unicode grows.

David

> /Roger
>

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