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[Bug 3969] Assertions: problems with basic concepts

From: <bugzilla@wiggum.w3.org>
Date: Fri, 10 Nov 2006 18:02:15 +0000
CC:
To: www-xml-schema-comments@w3.org
Message-Id: <E1Giahj-0002aj-F7@wiggum.w3.org>

http://www.w3.org/Bugs/Public/show_bug.cgi?id=3969

           Summary: Assertions: problems with basic concepts
           Product: XML Schema
           Version: 1.1 only
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Structures: XSD Part 1
        AssignedTo: cmsmcq@w3.org
        ReportedBy: fabio@cs.unibo.it
         QAContact: www-xml-schema-comments@w3.org


Concepts
-------
1) Report AND Assert: Having both assert and report in the syntax seems (and
has always seemed) redundant and unclean. Both can be expressed in terms of the
other so only one is necessary. Having them both and calling them assert and
report are the last vestige of Schematron, and considering that the current
proposal in many ways differ from Schematron (not least the fact that we
associate CC to types rather than elements) makes the Schematron-like syntax
confusing and uncalled for.

2) Why should assert and report be elements? Getting rid of the two elements
would allow us to get rid of the element itself, and just rely on a single
attribute (e.g., test) to be placed anywhere, but most appropriately in the
complexType element itself.

3) CC and extensions: CC always provide restrictions to the expressed content
model. It is my impression that so far derivation by restriction and derivation
by extension have been kept carefully separated, and features of one have never
allowed when using the other (AFAIK I cannot restrict an optional behavior when
extending a type). Now CC allow me to mix the two approaches: I can practically
(if not theoretically) restrict a type with CC while extending it with the
content model expression. I have nothing per se against this, but it is a
strong deviation with the past. Do we all like it?
Received on Friday, 10 November 2006 18:02:33 GMT

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