Synthetic Infosets and Conformance

Hello,

     According to Section 3, "Conformance", of the "XML Information Set" 
specification [1], a specification that refers to the Infoset 
specification must do the following.

Indicate the information items and properties that are needed to implement 
the specification. (This indirectly imposes conformance requirements on 
processors used to implement the specification.) 
Specify how other information items and properties are treated (for 
example, they might be passed through unchanged). 
Note any information required from an XML document that is not defined by 
the Infoset. 
Note any difference in the use of terms defined by the Infoset (this 
should be avoided). 


     Appendix D of the "XML Schema: Structures" specification [2] 
indicates that it requires attribute information items to have at least 
the [local name], [namespace name] and [normalized value] properties. 
Further, that appendix indicates that there is no destructive alteration 
of the information set in creating the synthetic infoset that results from 
schema assessment (PSVI) - only additive contributions.

     Section 3.4.5 of Schema: Structures [3] indicates that in some 
circumstances, the [attributes] property of an element information item in 
the PSVI may contain attribute information items that were not present in 
the input information set, that have the properties [local name], 
[namespace name], [schema normalized value], [schema default], [validation 
context], [validity], [validation attempted] and [schema specified].

     This means that the [attributes] property of an element information 
item in the PSVI could have some attribute information items that have a 
[normalized value] property while others do not, and could have some 
attribute information items that have a [schema normalized value] while 
others do not.  This is not the same as the properties being present with 
one of the special values "no value" or "unknown".

     Was it intended that a specification that conforms to "XML 
Information Set" could define an infoset that has two information items of 
the same kind with disjoint sets of properties?

Thanks,

Henry
[1] http://www.w3.org/TR/xml-infoset/#conformance
[2] http://www.w3.org/TR/xmlschema-1/#infoset
[3] http://www.w3.org/TR/xmlschema-1/#section-Complex-Type-Definition-Information-Set-Contributions
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Henry Zongaro      XML Parsers development
IBM SWS Toronto Lab   Tie Line 969-6044;  Phone (905) 413-6044
mailto:zongaro@ca.ibm.com