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Re: substitutionGroup and anyType

From: Hugh Wallis <hugh_wallis@hyperion.com>
Date: Wed, 12 Feb 2003 13:08:29 -0500
Message-ID: <002101c2d2c1$bece2fe0$c2941bac@hyperion.com>
To: "Jeni Tennison" <jeni@jenitennison.com>
Cc: <xmlschema-dev@w3.org>

Hmm - but at http://www.w3.org/TR/xmlschema-1/#Type_Definition_Summary it

[Definition:]  Except for a distinguished ·ur-type definition·, every ·type
definition· is, by construction, either a ·restriction· or an ·extension· of
some other type definition. The graph of these relationships forms a tree
known as the Type Definition Hierarchy.


[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

Which I would of thought meant that any type, simple or complex, can be
derived from anyType


----- Original Message -----
To: "Hugh Wallis" <hugh_wallis@hyperion.com>
Cc: <xmlschema-dev@w3.org>
Sent: Wednesday, 12 February, 2003 12:00 PM
Subject: Re: substitutionGroup and anyType

Hi Hugh,

> Validates fine in XML-Spy, Topologi Schematron Validator (uses MSXML
> 4.0), using JAXP/Xerces2 but not using .NET validator which gives
> the error message
> 'library' cannot be a member of the substitution group with head
> element 'item'. An error occurred at
> file:///C:/temp/AnyType.xsd(4,2)
> Which is right?

Hmm... I think that technically the .NET validator is right because
the type of the library element (xs:string) is a simple type
definition and therefore, based on the Schema Component Constraint:
Type Derivation OK (Simple) [1] isn't validly derived from xs:anyType.

On the other hand, I think that the spirit of the XML Schema spec is
that xs:string is a subtype of xs:anyType so perhaps I'm misreading
that constraint and the other validators are correct.

Sorry for such a wooly answer,


[1] http://www.w3.org/TR/xmlschema-1/#cos-st-derived-ok

Jeni Tennison
Received on Wednesday, 12 February 2003 13:09:01 UTC

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