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RE: Section 5 vs Schema

From: Williams, Stuart <skw@hplb.hpl.hp.com>
Date: Fri, 25 Jan 2002 16:43:10 -0000
Message-ID: <5E13A1874524D411A876006008CD059F1928FB@0-mail-1.hpl.hp.com>
To: "'Marc Hadley'" <marc.hadley@sun.com>
Cc: XML Protocol Discussion <xml-dist-app@w3.org>, Martin Gudgin <marting@develop.com>
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 11:43:23 GMT

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