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RE: Section 5 vs Schema

From: Don Box <dbox@microsoft.com>
Date: Fri, 25 Jan 2002 15:12:29 -0800
Message-ID: <CFC4F26947496E4092489B24256149580414BF1E@svc-msg-02.northamerica.corp.microsoft.com>
To: "XML Protocol Discussion" <xml-dist-app@w3.org>
+1 from me as well. I believe SOAP (and WSDL) should deal exclusively in
terms of XML Schema types and defer language/type system mappings to
specs that are independent of SOAP.

DB

> -----Original Message-----
> From: Christopher Ferris [mailto:chris.ferris@sun.com]
> Sent: Friday, January 25, 2002 8:47 AM
> To: Williams, Stuart
> Cc: 'Marc Hadley'; XML Protocol Discussion; Martin Gudgin
> Subject: Re: Section 5 vs Schema
> 
> +1 to this being primer material vs spec
> 
> Cheers,
> 
> Chris
> 
> Williams, Stuart wrote:
> 
> > Hi Marc,
> >
> > On the surface this looks really good, but I'm wondering whether it
> takes a
> > lid off of a can of worms. So far we have avoided defining any
concrete
> > programming language bindings - there were some early threads,
starting
> at
> > [1,2], on the topic of whether or not we were taking on language
> bindings .
> >
> > I kind of feel that if we're going to use programming language
bindings
> in
> > examples (particularly in the spec.) then we should do the whole job
of
> > defining a language binding for the programming language(s) that get
> used in
> > examples in normative parts of the spec.
> >
> > If the PL binding examples are mostly illustrative rather than
> definitive,
> > then the primer may be a better place to include fragments that hint
at
> > language bindings.
> >
> > Regards
> >
> > Stuart
> > [1]
http://lists.w3.org/Archives/Public/xml-dist-app/2000Nov/0081.html
> > [2]
http://lists.w3.org/Archives/Public/xml-dist-app/2000Nov/0051.html
> >
> >
> >
> >>-----Original Message-----
> >>From: Marc Hadley [mailto:marc.hadley@sun.com]
> >>Sent: 25 January 2002 15:01
> >>To: Martin Gudgin
> >>Cc: XML Protocol Discussion
> >>Subject: Re: Section 5 vs Schema
> >>
> >>
> >>The ETF discussed this issue in a recent telcon and would like to
> >>propose a change to section 3.4 of the current editors draft[1] to
> >>lessen the schema bias in the examples by showing the mapping from
> >>programming language compound types to SOAP encoding.
> >>
> >>e.g. the first example in section 3.4.1 shows an instance of a book
> >>structure and a schema that describes the structure. This would be
> >>replaced with a C language struct definition and a SOAP encoding
> >>serialisation of the structure, e.g.
> >>
> >>BEGIN EXCERPT
> >>
> >>The following structure:
> >>
> >>struct Book
> >>{
> >>    char *author;
> >>    char *preface;
> >>    char *intro;
> >>} book = {"Henry Ford", "Preface text", "Intro Text"};
> >>
> >>would be encoded as follows without a schema
> >>
> >><Book xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
> >>        xmlns:enc="http://www.w3.org/2001/12/soap-encoding">
> >>    <author xsi:type="enc:string">Henry Ford</author>
> >>    <preface xsi:type="enc:string">Preface text</preface>
> >>    <intro xsi:type="enc:string">Henry Ford</intro>
> >></Book>
> >>
> >>or as follows if a schema is available
> >>
> >><e:Book xmlns:e="http://example.org/2001/12/books">
> >>    <e:author>Henry Ford</e:author>
> >>    <e:preface>Preface text</e:preface>
> >>    <e:intro>Henry Ford</e:intro>
> >></e:Book>
> >>
> >>END EXCERPT
> >>
> >>Comments, flames etc.
> >>
> >>Marc (on behalf of the ETF)
> >>
> >>[1] http://www.w3.org/2000/xp/Group/1/10/11/soap12-part2.html
> >>
> >>Martin Gudgin wrote:
> >>
> >>
> >>>SOAP 1.2 Part 2 Section 4[1] ( old section 5 ) defines a set
> >>>
> >>of encoding
> >>
> >>>rules for mapping from programmatic type systems to XML.
> >>>
> >>>There was some discussion on the last editors conference
> >>>
> >>about how to deal
> >>
> >>>with issue 17[2] regarding the schemas that appear in
> >>>
> >>section 5. I took an
> >>
> >>>action to start discussion about this on this list. Please
> >>>
> >>note I will be on
> >>
> >>>holiday from today and will not be back until the New Year
> >>>
> >>so will not be
> >>
> >>>able to actively participate until then, hopefully you'll
> >>>
> >>all have nailed
> >>
> >>>the issue by then!
> >>>
> >>>One suggestion was that section 5 actually defines an
> >>>
> >>implicit schema so
> >>
> >>>each mapping from some programmatic type essentially defines
> >>>
> >>a schema type.
> >>
> >>>This seems reasonable but at the same time feels a little
> >>>
> >>odd. We have
> >>
> >>>section 5 because when SOAP 0.9, 1.0 and 1.1 were written
> >>>
> >>XML Schema was not
> >>
> >>>done, we didn't have an XML based type system. So we had to
> >>>
> >>start from a
> >>
> >>>type system we did have. So Section 5 defines a set of rules
> >>>
> >>for mapping
> >>>from programmatic type systems iuntNow that XML Schema is done it
is
> >>
> >>>possible to define the messages being exchanged entirely in
> >>>
> >>XML Schema
> >>
> >>>without reference to any programmatic type system. Mapping to the
> >>>programmatic type system ( if any ) at either end of the
> >>>
> >>exchange is an
> >>
> >>>implementation detail.
> >>>
> >>>So, given that we have XML Schema, does it make sense to
> >>>
> >>infer a schema from
> >>
> >>>some other type system?
> >>>
> >>>And if it does, what do we do about examples in the spec. It
> >>>
> >>seems very
> >>
> >>>strange to say 'we start from a programmatic type system'
> >>>
> >>and then only show
> >>
> >>>schemas! We are defining a language binding, even if we
> >>>
> >>never show a Java
> >>
> >>>class or a C struct or whatever.
> >>>
> >>>OK, that's it. I hope the discussion is fruitful, I'll read
> >>>
> >>through it when
> >>
> >>>I get back from holiday.
> >>>
> >>>Regards
> >>>
> >>>Martin Gudgin
> >>>DevelopMentor
> >>>
> >>>
> >>>
> >>>[1] http://www.w3.org/TR/2001/WD-soap12-part2-20011002/#soapenc
> >>>[2] http://www.w3.org/2000/xp/Group/xmlp-issues.html#x17
> >>>
> >>>
> >>
> >
> 
Received on Friday, 25 January 2002 18:13:02 GMT

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