Re: [xsl] Distinguish between empty string and no children, in XPath 2?

["Andrew Welch" <andrew.j.welch@xxxxxxxxx>]

>> Let's say we have a schema (maybe expressed in XML Schema, but not
>> necessarily so), that allows this instance document:
>>
>> <top>
>>  <txt>This is text</txt>
>>  <books>
>>    <book>Tarzan</book>
>>    <book>Harry Potter</book>
>>  </books>
>> </top>
>>
>> The text /top/txt may be empty, and the element /top/books may have no
>> children, so this instance document is also allowed:
>>
>> <top>
>>  <txt/>
>>  <books/>
>> </top>
>>
>> I now want to write an XPath expression that selects all nodes that do
>> not have child elements in the schema. It would always select /top/txt
>> and it would never select /top/books, even in the second example
>> above.
>>
>> With XPath 1.0, this is not possible, since schema information is not
>> used there. But can it be done in XPath 2.0?

Ken:
> Unless, perhaps, you had the flexibility in your schema to define a base
> type with your own name that is a very generic type that allows only element
> children of any name, and then specialize all of your element-content
> element types on that type restricting each one to the child elements for
> that particular type.  Then in your XPath you can test elements as being an
> element of your named generic type and it would be checking that the element
> is one that has element content.

Instead of applying the xpath to the instance document, don't you just
want to apply it to the schema - select all simpleTypes ?

I don't know if you can tell from the PSVI whether a given type is a
simpleType or complexType, but that would do it... maybe "castable as
xs:anyAtomicType" ?

Just thinking out loud...



-- 
Andrew Welch
http://andrewjwelch.com
Kernow: http://kernowforsaxon.sf.net/