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On Thu, 20 Oct 2005, Alan Gutierrez wrote:
> I'm confused by the wording of...
>
> http://www.w3.org/TR/xpath-datamodel/#TypedValueDetermination
>
> ...where it discusses the value value determination for lists.
>
> "For each of these lexical forms, the type of the corresponding
> item is found in {item type definition}."
>
> I can't figure out if the {item type definition} is attached to
> the list as a property, or an index property, or if it attached
> to the item within the list. The mention of recursion implies
> the latter.
I think one would need a larger quote to understand the question...:
"The types of the items in the typed value of a node are determined by
a recursive process called typed value determination. This process
begins with T, the schema type of the node itself, as represented in
the PSVI. The type T has a variety, which is either atomic, union, or
list. The typed value determination process is defined as follows:
<skip other cases>
- If the {variety} of T is list, the [schema normalized value] of the
node is considered to be a space-separated list of lexical forms,
each of which has its own type. For each of these lexical forms, the
type of the corresponding item is found in {item type definition}.
This type is then substituted for T, and the typed value
determination process is invoked recursively for each member of the
list."
Brief answer: {item type definition} is a property of T, the schema's list
_type_ that validated the value in question. It is not a property the
list _value_.
One could arrive to this understanding after meditating over WXS Part 2,
4.1.1 http://www.w3.org/TR/xmlschema-2/#rf-defn
[I tried to find a description of Typed Value Determination in XQuery
Formal Semantics, but apparently it just refers to the above-quoted
definition (see 3.5.2,
http://www.w3.org/TR/2005/WD-xquery-semantics-20050915/#id-typed-value)
Too bad. I guess, the reason is that formalizing this notion would
require formalizing most of WXS, which is any formalist's nightmare!]
Vladimir
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