[XQuery] XQ-IBM-026 Function conversion rules

In XPath/XQuery Section 3.1.5, Function Calls, under "Function Conversion 
Rules", after atomization, we find the following rule: "Each item in the 
atomic sequence that is of type xdt:untypedAtomic is cast to the expected 
atomic type." This is not completely specified for certain built-in 
functions such as fn:abs() in which the expected parameter type is 
"numeric", which includes integer, decimal, float, and double. To complete 
the specification, we should insert the following sentence after the rule 
cited above: "For parameters of built-in functions where the expected type 
is specified as numeric, arguments of type xdt:untypedAtomic are cast to 
xs:double."

--Don Chamberlin