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RE: Datatypes questions

From: Biron,Paul V <Paul.V.Biron@kp.org>
Date: Thu, 13 May 1999 11:44:04 -0700
Message-Id: <376E771642C1D2118DC300805FEAAF43B5B1@pars-exch-1.ca.kp.org>
To: "'Paul Prescod'" <paul@prescod.net>
Cc: "'www-xml-schema-comments@w3.org'" <www-xml-schema-comments@w3.org>
Sorry, forgot to include the url for the next generation forms work:

[1] http://www.w3.org/MarkUp/Group/Forms/

pvb

> -----Original Message-----
> From:	Biron,Paul V 
> Sent:	Thursday, May 13, 1999 11:43 AM
> To:	'Paul Prescod'
> Cc:	www-xml-schema-comments@w3.org
> Subject:	RE: Datatypes questions
> 
> 	-----Original Message-----
> 	From:	Paul Prescod [SMTP:paul@prescod.net]
> 	Sent:	Wednesday, May 12, 1999 2:58 PM
> 	To:	Biron, Paul V; petsa@us.ibm.com;
> www-xml-schema-comments@w3.org
> 	Subject:	Datatypes questions
> 
> 	> "Issue (uri-scheme-facet): should we have a facet to allow a
> limitation 
> 	> to a specific scheme? It might be useful to able to say that
> something 
> 	> was not only a URI, but that it was a "mailto" and not a
> "http://...". 
> 
> 	No. I think it would be in bad form to restrict by protocol. If I
> invent
> 	httpplus next week my schema should not restrict me from using it.
> The
> 	much more interesting sort of restriction is by target -- i.e. "this
> link
> 	must go to an XML element with GI foo." But that might be out of
> scope.
> 
> By "bad form" do you mean that individual type designers (and schema
> authors) should steer clear of such things, and hence, we should not give
> them the freedom to do so if they want to?
> 
> The inclusion of that issue was my idea.  The intention is to keep the
> basic uri datatype, but to allow schema designers to create their own
> user-generated subtypes which were restricted by scheme.  Including this
> facet would not force anyone to use it, but would merely allow those who
> wanted it to be able to use it.
> 
> The use case would be a schema author who wanted to do something like the
> following in their own schema:
> 
> <datatype name="mailto">
> 	<basetype name="uri"/>
> 	<scheme>mailto</scheme>
> </datatype>
> <datatype name="phone">
> 	<basetype name="uri"/>
> 	<scheme>tel</scheme>
> </datatype>
> <!-- see http://www.w3.org/Addressing/schemes for a note on the tel:
> scheme -->
> <elementType name="contactInfo">
> 	<all>
> 		<elementType name="name">
> 			<datatypeRef name="string"/>
> 		</elementType>
> 		...
> 		<elementType name="phone">
> 			<datatypeRef name="phone"/>
> 		</elementType>
> 		<elementType name="email">
> 			<datatypeRef name="mailto"/>
> 		</elementType>
> </elementType>
> 
> This would allow instances such as the following to be flagged as schema
> invalid
> 
> <contactInfo>
> 	<name>Paul V. Biron</name>
> 	<phone>tel:+1-626-685-3529</phone>  <!-- valid tel: -->
> 	<email>http://www.kp.org</email>        <!-- invalid mailto: -->
> </contactInfo>
> 
> 	> Issue (picture-or-regex): Should the values of the 
> 	> [Lexical representation] facet be pictures, regexs, both or some 
> 	> other mechanism? 
> 
> 	Not only do we need both, I'm going to argue that we should be
> allowed to
> 	specify both for the same user-defined data type. Pictures are nice
> and
> 	simple. Regexps are powerful. One feature that pictures support that
> 	regexps do not is nice, guided editing. ###-####-#### can be easily
> 	rendered into a GUI. A regexp cannot. In the (admittedly rare) case
> that a
> 	type had both I would expect the picture to be used for guided
> editing and
> 	the regular expression for more complicated constraints. Of course
> the
> 	input would have to match both.
> 
> Like Ashok, my initial reaction to allowing both a picture and a regex on
> the same datatype is that doing so would be a bad idea.
> 
> The intention of having the picture constraints was that it might be
> simpler for some users to write (and understand) simple constraints not to
> help UI builders.  I'm hoping the next generation XHTML Forms work [1]
> will provide the kind of UI pictures you want.
> 
> pvb
Received on Thursday, 13 May 1999 14:52:54 GMT

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