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RE: wsdl:import semantics is different from xs:import

From: Jonathan Marsh <jmarsh@microsoft.com>
Date: Mon, 25 Jul 2005 07:58:42 -0700
Message-ID: <7DA77BF2392448449D094BCEF67569A50854F7FF@RED-MSG-30.redmond.corp.microsoft.com>
To: <noah_mendelsohn@us.ibm.com>
Cc: <public-ws-desc-comments@w3.org>, <w3c-xml-schema-wg@w3.org>

The WG agreed to incorporate this clarification.  Thanks!

> -----Original Message-----
> From: noah_mendelsohn@us.ibm.com [mailto:noah_mendelsohn@us.ibm.com]
> Sent: Thursday, June 02, 2005 4:22 PM
> To: Jonathan Marsh
> Cc: public-ws-desc-comments@w3.org; w3c-xml-schema-wg@w3.org
> Subject: RE: wsdl:import semantics is different from xs:import
> 
> Again writing just for myself, and similar in spirit to the quibble
> raised
> in my note of ealier today.  Your proposed text says:
> 
> > components imported by one of the imported
> > documents are not available to the original importing
> > document unless the are imported
> > directly by that document.
> 
> This is not quite true of schema, in that it implies that "components
> are
> imported by a document."  Components are imported by a schema
> processor
> using most any rules it likes.  One such rule is that there can be
> schemaLocation hints on an import, and the processor may honor such a
> hint.  Note however that the effect is then pervasive.  Thus, if we
> have
> composed into the same schema:
> 
> In schema document 1:
> 
>         <import namespace="ns1URI" schemaLocation="docURI"/>
>         <element name="n" type="ns1:t" xmlns:ns1="ns1URI"/>
> 
> In schema document 2:
> 
>         <import namespace="ns1URI"/>
>         <element name="n" type="ns1:t" xmlns:ns1="ns1URI"/>
> 
> It >MUST< be the case that either both references to ns1:t succeed or
> neither succeed.  That's true regardless of whether the reason that
> the
> component for type ns1:t was brought in by following that first
> schemaLocation hint.   The principle purpose of import is not to
> import
> components, but rather to license references to components in the
> namespace.    I wonder if you might do better to say:
> 
> "The WSDL import element information item is
> modeled after the XML Schema import element
> information item (see [XML Schema: Structures],
> section 4.2.3 "References to schema components
> across namespaces"). Specifically, it can be used
> to import components from WSDL descriptions that
> do not share a target namespace with the importing
> document.
> 
> As with XML schema, each document making references
> to components in a given (foreign) namespace MUST
> have an import for that namespace (but not necessarily
> providing a schemaLocation identifying the document
> in which the referenced component is declared).  In
> other respects, the visibility of components is
> pervasive; if two WSDL documents import the same
> namespace then they will have access to the same
> components from the imported namespace (I.e.
> regardless of which, if any, schemaLocations
> are provided on the respective imports.)"
> 
> That's my understanding of how XML Schema works.  Presuming I have
> that
> right, I believe the position of the Schema WG would be that you
> should
> either change your description to indeed agree with schema's behavior,
> or
> else back off on the claim that WSDL is indeed modeled on Schema.
> 
> I should say that I think we're all grateful for your efforts both to
> line
> up with our behavior and to get the details right.  I'm sorry that I
> did
> not notice these nuances in your redrafting earlier.  I'm sure other
> members of the Schema WG will weigh in to the extent they disagree
> with my
> analysis.  I hope this is helpful.
> 
> Noah
> 
> 
> --------------------------------------
> Noah Mendelsohn
> IBM Corporation
> One Rogers Street
> Cambridge, MA 02142
> 1-617-693-4036
> --------------------------------------
> 
> 
> 
Received on Monday, 25 July 2005 14:59:04 GMT

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