W3C home > Mailing lists > Public > www-xml-schema-comments@w3.org > April to June 2001

What exactly is a pattern facet for a list datatype?

From: Alexander Falk <al@altova.com>
Date: Thu, 24 May 2001 03:16:36 +0200
Message-ID: <0FED160BABE4D311AD2E0050DA465785530F7D@medusa.icon.at>
To: www-xml-schema-comments@w3.org
I have a question regarding the used of a pattern facet on a list datatype,
which has come up during the implementation of the final XML Schema
Recommendation in our XML Spy product line:

In Part 2 Datatypes, Section 2.5.1.2 Definition of the list datatype
(http://www.w3.org/TR/xmlschema-2/#dt-list), there is a list of facets that
can be applied to a list dataype:

	When a datatype is ·derived· from a ·list· datatype, the following
·constraining facet·s apply: 

	·length· 
	·maxLength· 
	·minLength· 
	·enumeration· 
	·pattern· 
	·whiteSpace· 

Which brings up the interesting question, on what a pattern for a list
datatype really means: is this pattern to be applied to each element in the
list, or should this be a pattern for the lexical space of the entire list?
Furthermore, under 4.1.4 Simple Type Definition Validation Rules, there is
no reference regarding what to do with such a pattern for a list datatype.
And we have been unable to find any other reference to this.

Also we found it odd, that for all the built-in derived datatypes (NMTOKENS,
IDREFS, ENTITIES), the "pattern" facet is missing from the respective
listing of the constraining facets:

	3.3.5.1 Constraining facets
	NMTOKENS has the following ·constraining facets·: 

	length 
	minLength 
	maxLength 
	enumeration 
	whiteSpace 

	3.3.10.1 Constraining facets
	IDREFS has the following ·constraining facets·: 

	length 
	minLength 
	maxLength 
	enumeration 
	whiteSpace 

	3.3.12.1 Constraining facets
	ENTITIES has the following ·constraining facets·: 

	length 
	minLength 
	maxLength 
	enumeration 
	whiteSpace 

This all leads me to conclude that 2.5.1.2 Definition of the list datatype
should probably not list "pattern" as one of the applicable facets for list
datatpyes. Is this something we have overlooked during the PR phase, or is
there any deeper (and well hidden) reason behind this?

Any clarification would be highly anticipated!

Thanks,

Alexander

... Alexander Falk
... President & CEO of Altova, Inc. - The XML Spy Company
... Member of the W3C Advisory Committee
... Member of the W3C XML Schema Working Group

=========================================================================
XML Spy 3.5  -  the first true Integrated Development Environment for XML
Visit http://www.xmlspy.com/ to download a free 30-day evaluation version
=========================================================================
Received on Wednesday, 23 May 2001 21:16:45 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Sunday, 6 December 2009 18:12:50 GMT