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Re: Section 5 vs Schema

From: Christopher Ferris <chris.ferris@sun.com>
Date: Fri, 25 Jan 2002 11:46:54 -0500
Message-ID: <3C518BFE.4070508@sun.com>
To: "Williams, Stuart" <skw@hplb.hpl.hp.com>
CC: "'Marc Hadley'" <marc.hadley@sun.com>, XML Protocol Discussion <xml-dist-app@w3.org>, Martin Gudgin <marting@develop.com>
+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 11:48:12 GMT

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