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RE: CR-21: Drop use of xsi:type as determinant for unions?

From: Asir S Vedamuthu <asirv@webmethods.com>
Date: Thu, 1 Feb 2001 09:22:40 -0500
To: "Martin Gudgin" <marting@develop.com>
Cc: "XML Schema Comments" <www-xml-schema-comments@w3.org>
Message-ID: <NPENICOLABLCDIJKMGEMOEIKCBAA.asirv@webmethods.com>
NOPE. I am not satisfied with the decision taken by the WG on this issue.
First, this issue was never opened and discussed. Second, I agree that it is
a useful feature. Third, I am NOT CONVINCED that it is well-defined. 'Cos,

CR spec doesn't say that is impossible to override the evaluation order if
the membertypes are anonymous types / combination of anonymous and named
types. Or, what happens if there are constraining facets on the union type,
say enumeration and pattern (s). Here is one example,

A.xsd
<xsd:element name='size'>
    <xsd:simpleType>
      <xsd:union>
        <xsd:simpleType>
          <xsd:restriction base='integer'>
		<xsd:minInclusive value="10"/>
	    </xsd:restriction>
        </xsd:simpleType>
        <xsd:simpleType>
          <xsd:restriction base='string'>
		<xsd:enumeration value="large"/>
		<xsd:enumeration value="medium"/>
		<xsd:enumeration value="small"/>
		<xsd:enumeration value="01"/>
	    </xsd:restriction>
        </xsd:simpleType>
      </xsd:union>
    </xsd:simpleType>
</xsd:element>

A.xml
...
(1)	<size>1</size>
(2)	<size>large</size>
(3)	<size xsi:type='xsd:string'>01</size>
...

(1) and (2) validate OK. In case (3), is 'xsd:string' a member of this
anonymous union type? NOPE

I would like my dissent on this decision be recorded. But, it is not grave
enough for the Director.

Regards, Asir S Vedamuthu
-----Original Message-----
From: Martin Gudgin [mailto:marting@develop.com]
Sent: Monday, January 22, 2001 3:35 AM
To: Asir S Vedamuthu
Cc: XML Schema Comments
Subject: CR-21: Drop use of xsi:type as determinant for unions?


Dear Asir

The W3C XML Schema Working Group has spent the last several weeks
working through the comments received from the public on the Candidate
Recommendation (CR) of the XML Schema specification.  We thank you for the
comments you made on our specification during our CR comment period, and
want to make sure you know that all comments received during the CR comment
period have been recorded in our CR issues list
(http://www.w3.org/2000/12/xmlschema-crcomments.html).

Among other issues, you raised the point registered as issue CR-21: Drop use
of xsi:type as determinant for unions?

The Schema Working Group declined to adopt the proposal on the grounds that
the functionality is useful and is also well-defined. However I would note
that the Working Group did vote to change the Type derivation OK [Simple]"
constraint to read "Type allowed [Simple]" on the grounds that the members
of a union type are, as you pointed out, not derived from it.

It would be helpful to us to know whether you are satisfied with the
decision taken by the WG on this issue, or wish your dissent from the
WG's decision to be recorded for consideration by the Director of
the W3C.

Regards

Martin Gudgin
XML Schema Working Group
Received on Thursday, 1 February 2001 09:19:45 GMT

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