Re: [xml-dev] Compatibility for XML attribute types with schemas

["Christopher R. Maden" <crism@maden.org>]

At 11:48 12-10-2001, Elliotte Rusty Harold wrote:
>Most of the XML simple types in the W3C XML Schema Language -- e.g. 
>NOTATION, NMTOKEN, iD, IDREF, etc. -- carry a compatibility rule; for example:
>
>For compatibility (see Terminology (§1.4) 
><http://www.w3.org/TR/xmlschema-2/#terminology> ) *NMTOKEN* should be used 
>only on attributes.
>
>How important is this? Would it really be a compatibility problem to say 
>that an element must have type NMTOKEN? or be an ID? How would this be 
>incomaptible with standard XML? The resulting document would still be 
>well-formed and perhaps DTD valid. Nothing in the schema would change 
>this. Of course, these constraints could not be used on elements in a DTD. 
>However, netiher could a constraint that an element be required to contain 
>an integer, whihc is acceptable in schemas.

I suspect (with no inside knowledge whatsoever) that it's more of a 
deprecation.  The only reason to use the XML 1.0-derived types is when 
converting a DTD into XSDL (or creating XSDL from which a DTD will be 
derived), in which case these types would only show up in attributes.  I 
suspect that when creating an XSDL from scratch, there will usually be a 
more appropriate type than the XML 1.0 ones.

-Chris
-- 
Christopher R. Maden, Principal Consultant, HMM Consulting Int'l, Inc.
DTDs/schemas - conversion - ebooks - publishing - Web - B2B - training
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