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

From: Mark Seaborne <MSeaborne@origoservices.com>
Date: Tue, 3 Sep 2002 15:40:48 +0100
Message-ID: <DC65AE678B89004B9CCB202E19482CC704FAD9@mail.origoservices.local>
To: "David Cleary" <davec@progress.com>, <AndrewWatt2001@aol.com>, <www-forms@w3.org>

-----Original Message-----
From: David Cleary [mailto:davec@progress.com]
Sent: 03 September 2002 14:56
To: AndrewWatt2001@aol.com; www-forms@w3.org
Subject: RE: Schema Modularisation in XForms (Was: xslt stylesheet for
xforms to xhtml)



>Replace XForms with SOAP and you see that by doing so, you kill interop and
>the usefullness of the technology. Imagine a world where web pages used
>different syntaxs for its schema/dtd, and a browser couldn't display a page
>without understanding that syntax. You would have a proprietary web.

>You may dislike XML Schema, but it is the schema language of the W3C and the
>one most industry players with the exception of Sun have outstanding support
>for. It is the schema language of Web Services, and XForms and Web Services
>compliment each other. Allowing XForms to use plugable languages for the
>model will lead to a proprietary spec that will be useless on the web.

>As an example, although Microsoft is using XML Schema heavily across all
>their tools and technologies so this isn't realistic, what you propose would
>allow Microsoft to use say XDR to model an XForm. Then only Windows and
>Internet Explorer could handle it. It would be a valid XForms
>implementation, and with 90% of the market, would work most of the time, but
>it wouldn't be right. Relax NG ceratinly has its uses, but interop over the
>web isn't one of them.

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.

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. 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. 

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!


All the best

Mark
Received on Tuesday, 3 September 2002 10:41:14 GMT

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