> i know its late in the day re XSLT / XPATH 2.0 drafts,
> 
> but doesnt this scenario sort of 'scream out' for a boolean function
> that tests for type, both basic (node, string, number) and schema ?
> 

There is such a construct: e.g. ($x instance of xs:decimal)

But in this case, I interpreted the requirement as being not to test whether
the attribute had a numeric type (ie. was defined as a number in the
schema), but whether its value had the lexical form of a number. The XPath
2.0 construct for this is ($x castable as xs:decimal).

Michael Kay
http://www.saxonica.com/