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As I mentioned previously, the seemingly contradictory dual nature of the ur-type is a known issue in the spec which has been addressed. More info at http://lists.w3.org/Archives/Member/w3c-xml-schema-ig/2002Jan/0065.html I assume an erratum will be published shortly. -- This posting is provided "AS IS" with no warranties, and confers no rights. You assume all risk for your use. (c) 2002 Microsoft Corporation. All rights reserved. > -----Original Message----- > From: Jeff Lowery [mailto:jlowery@s...] > Sent: Friday, March 22, 2002 1:01 PM > To: Jeff Lowery; Thomas B. Passin; xml-dev@l... > Subject: RE: Who can implement W3C XML Schema ? > > > Okay, I wrote my previous message at 3:30 am, but now I'm > actually ready to think about this cute little issue. > > It's an interesting one, because (as it's been noted > previously in this thread), the anyType is both simple and complex. > > If we treat the anyType as complex in the following: > > <element name="myElem"> > <complexType> > <complexContent> > <restriction base="anyType"/> > </complexContent> > </complexType> > </element> > > we can come to the (correct) conclusion that since none of > the (infinite) members of the anyType are mentioned, no > element or attribute content is allowed for myElem. There's a > related example in the Primer (2.5.3): > > <xsd:element name="internationalPrice"> > <xsd:complexType> > <xsd:complexContent> > <xsd:restriction base="xsd:anyType"> > <xsd:attribute name="currency" type="xsd:string"/> > <xsd:attribute name="value" type="xsd:decimal"/> > </xsd:restriction> > </xsd:complexContent> > </xsd:complexType> > </xsd:element> > > which is equivalent to: > > <xsd:element name="internationalPrice"> > <xsd:complexType> > <xsd:attribute name="currency" type="xsd:string"/> > <xsd:attribute name="value" type="xsd:decimal"/> > </xsd:complexType> > </xsd:element> > > > The internationalPrice element contains these two attributes, > no child elements, and no data content. I remember checking > the normative spec on this and the primer appears to be correct. > > But what is interesting is the simpleType nature of anyType. > One could see an (incorrect) implemenation regarding the > following to definitions as being > equivalent: > > <elementname="myElem"> > <complexType> > <complexContent> > <restriction base="anyType"/> > </complexContent> > </complexType> > </element> > > > <element name="myElem" type="anySimpleType"/> > > And why not? The former definition merely restricts the > children and attributes of a complex type by omitting them. > But what of the data content? If you look at 2.2.1 of Part 1 > of the spec, you see: > > [Definition:] A distinguished ur-type definition is present > in each *XML Schema*, serving as the root of the type > definition hierarchy for that schema. The ur-type definition, > whose name is anyType, has the unique characteristic that it > can function as a complex or a simple type definition, > according to context. Specifically, *restrictions* of the > ur-type definition can themselves be either simple or complex > type definitions. > > I still don't think that treating the two declarations above > as equivalent is correct, but the following would be > equivalent according to my > understanding: > > <elementname="myElem" mixed="true"> > <complexType> > <complexContent> > <restriction base="anyType"/> > </complexContent> > </complexType> > </element> > > <element name="myElem" type="anySimpleType"/> > > > However, I'm traipsing into corner cases here, so I would > gladly defer to those true spec mavens out there who spend a > lot of time teasing things out of the spec. I aim squarely > at the 80/20 point. Implementors of validating tools > unfortunately don't have that luxury. > > Ciao, > > Jeff > > > > -----Original Message----- > > From: Jeff Lowery [mailto:jlowery@s...] > > Sent: Friday, March 22, 2002 10:58 AM > > To: Thomas B. Passin; xml-dev@l... > > Subject: RE: Who can implement W3C XML Schema ? > > > > > > Hey, why single me out? If Eric isn't sure, how likely am I to be? > > > > "According to my understanding" (and how it's written in _my_ > > book [watch > > the elbows, Eric]), the element's content must be empty, since the > > restriction reiterates nothing of the anyType. But somebody > > pointed out an > > errata somewhere so my interpretation may be suspect. But I > > think it's what > > the primer has, also. (I'd check, but my laptop's battery is > > crapping out.) > > > > > Jeff Lowery, how about explaining this for us? > > > > > > Cheers, > > > > > > Tom P > > > > > > > > > ----------------------------------------------------------------- > > > The xml-dev list is sponsored by XML.org <http://www.xml.org>, an > > > initiative of OASIS <http://www.oasis-open.org> > > > > > > The list archives are at http://lists.xml.org/archives/xml-dev/ > > > > > > To subscribe or unsubscribe from this list use the subscription > > > manager: <http://lists.xml.org/ob/adm.pl> > > > > > > > ----------------------------------------------------------------- > > The xml-dev list is sponsored by XML.org <http://www.xml.org>, an > > initiative of OASIS <http://www.oasis-open.org> > > > > The list archives are at http://lists.xml.org/archives/xml-dev/ > > > > To subscribe or unsubscribe from this list use the subscription > > manager: <http://lists.xml.org/ob/adm.pl> > > > > ----------------------------------------------------------------- > The xml-dev list is sponsored by XML.org > <http://www.xml.org>, an initiative of OASIS <http://www.oasis-open.org> The list archives are at http://lists.xml.org/archives/xml-dev/ To subscribe or unsubscribe from this list use the subscription manager: <http://lists.xml.org/ob/adm.pl>
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