RE: [xsl] would like to simplify my XSLT

["Michael Kay" <mike@xxxxxxxxxxxx>]

> Undoubtedly there are subtle reasons that the designers of 
> XPath 2 have foreseen while disallowing union, intersect and 
> except to operate on any type of sequences, incl. atomic 
> types (even though there are other operators that yield the 
> same result).

You may have noticed that there are example user-written functions to do
value-based union, intersection, and difference of sets of atomic values in
an appendix of the F+O spec. They are there because (a) some WG members
wanted to provide the functionality, (b) others pointed out that they could
all be written as one-liners using existing facilities, and (c) everyone
wanted to reduce the number of functions and operators. Furthermore, (d)
it's not exactly obvious what the spec should be, e.g. ordering of the
result, promotion of numeric types, handling of NaN, etc, especially in
corner cases for example where you have two decimals that are not-equal to
each other but both equal to the same double.

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