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RE: Schema Modularisation in XForms (Was: xslt stylesheet for xfo rms to xhtml)

From: Tomayko, Ryan <Ryan_Tomayko@stercomm.com>
Date: Tue, 3 Sep 2002 12:28:20 -0400
Message-ID: <D037B3982A54D611BA5E0006293835400100B6AE@scidubmsg02.amr.stercomm.com>
To: David Cleary <davec@progress.com>, Mark Seaborne <MSeaborne@origoservices.com>, AndrewWatt2001@aol.com, www-forms@w3.org

> > I hope that people use the schema languages that seem most appropriate 
> > to their needs. After all XForms has invented its own schema language 
> > to make up for lack of features in W3C XML Schema and to provide 
> > support for well-formed XML.

> XForms did not invent their own schema language.

I think Mark was referring to the fact that processing binding expressions
results in infoset augmentation in much the same way that W3C XML Schema
processing results in infoset augmentation. Each attaches information to
nodes in a document. They provide different types of augmentation though
with some overlap:


augmentation     XForms      WXS
-----------------------------------------
readonly         Yes         No (at least, I don't think so)
relevant         Yes         No
type             Yes         Yes
constraint       Yes (xpath) Sort Of (regular expressions)
minOccurs        Yes         Yes
maxOccurs        Yes         Yes

- Ryan

-----Original Message-----
From: David Cleary [mailto:davec@progress.com] 
Sent: Tuesday, September 03, 2002 10:57 AM
To: Mark Seaborne; AndrewWatt2001@aol.com; www-forms@w3.org
Subject: RE: Schema Modularisation in XForms (Was: xslt stylesheet for
xforms to xhtml)



> Hmmm, all this seems a bit arbitrary to me. What you are saying is 
> that there can only be one schema language, because of the danger that 
> someone might implement something that only used their own, private 
> schema language. However, if a small company did this, they simply 
> wouldn't sell their product very widely - and this might actually be 
> fine for a niche market. If a Microsoft does the same, then everyone 
> else will support it, in the way most word processing packages support 
> a multitude of Word formats, past and present.

Not what I'm saying at all. If you are passing around XML data, both client
and server can validate that data against any schema language and still be
interoperable. However, that doesn't apply to SOAP and XForms. Both client
and server need to understand the schema language used, and that schema
language is tied to the data.

> I hope that people use the schema languages that seem most appropriate 
> to their needs. After all XForms has invented its own schema language 
> to make up for lack of features in W3C XML Schema and to provide 
> support for well-formed XML.

XForms did not invent their own schema language.

> We are thinking about
> using Relax and/or Schematron for the same reason (they are/will soon 
> be standards, and are more general purpose than XForms constraints). 
> If XForms supports Relax, then fine; if it doesn't, someone else will 
> come up with a mechanism for transforming Relax into W3C XML Schema 
> and/or XForms constraints. If vendors think that support for Relax, or 
> Schematron will sell their products, they will offer such mechanisms 
> built in to their XForms implementations. If not, a bit of 
> preprocessing may be in order.

If every client must support an arbitrary plugable language to determine the
XForms model, kind of defeats the "XML Schema is too complicated" argument.

> I don't think it really matters one way or the other - as long as we 
> can map between languages, which is the whole point of using XML for 
> such things in the first place. It is probably sufficient for you to 
> argue that XForms is quite complicated enough already, without adding 
> plug-in schema language support!

So you can get support for at least 3 schema languages on a mobile phone by
writing some mapping code? I don't think so. That is why XForms only
requires XML Schema datatype support as a minimum. And their ain't any
datatypes in Relax and Schematron in any case.

Dave
Received on Tuesday, 3 September 2002 12:29:09 GMT

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