Re: Potential new issue: PSVI considered harmful

Simon St.Laurent wrote:

> XQuery has taken a stab at reducing the PSVI to something manageable, 
> yes. (See [s1].)

This is exactly the problem.  I quote from 
http://www.w3.org/TR/query-datamodel/#psv

"The data model is defined in terms of the [XML Information
 Set] after XML Schema validity assessment. XML Schema validity
 assessment is the process of assessing an XML element information
 item with respect to an XML Schema and augmenting it and some or
 all of its descendants with properties that provide information
 about validity and type assignment. The result of schema validity
 assessment is an augmented Infoset, known as the Post
 Schema-Validation Infoset, or PSVI. "

It's just fine to want to use types and so on in XQuery (or any other 
work).  It's simply wrong to assert that types can exist only "after XML 
Schema validity assessment."  There is no way in the world to discover 
that some attribute value should be interpreted as a floating point 
number for purposes of range comparison, other than ascertaining whether 
the containing instance is valid?

An analogy: the PSVI is kind of like saying that the only way to 
ascertain a person's weight is to go through a complete top-to-bottom 
physical exam."   -Tim