Comments on RELAX NG 2001-06-08

[Rick Jelliffe <ricko@allette.com.au>]

Here are some comments on the recent version of RELAX that I hope may be
useful.

Issue 21. duplicateAttributes: prohibiting duplicate attributes
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Why not make duplicate attribute declaration operate in parallel?

Since it is impossible to have duplicates in XML, any regular expression can
only act as if it were a logical expression w.r.t. attributes. So any
operation that is not an OR will be an AND: sequence should AND, so ( @a,
@a ) would be perfectly fine:
@a AND @a which = @a.

Data Content
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I think it is a mistake to not allow full tokenizing and
regular-expression-parsing of data content or attribute values.  It merely
perpetuates one of W3C XML Schema's mistakes, which is the bizarre view that
structure stops at markup. (Or, perhaps, the more forgivable view that we
need to decompose a document into a tree according to markup, but we do not
need to decompose data content into a tree except for validation.)

I fear that making RELAX NG a minimized, tidied-up and more powerful version
of W3C XML Schemas will, unless W3C XML Schemas' greatest mistakes on scope
and use-cases are addressed, merely give us a well-groomed runt, and
squanders the opportunity for a serious schema language on boffinry.


Cheers and best wishes
Rick Jelliffe