[XQuery] SAG-XQ-004 Unordered

SAG-XQ-004 Unordered

We find that the concept of unordered() as a function, while it has some
theoretical justification, is very difficult to explain to users. This is
because it doesn't reflect the intended purpose: people call functions when
they want to perform some computation on a supplied value, not when they
want to tell the compiler to relax the rules on how the input is evaluated.

The decision also seems to be inconsistent with the decision to merge "order
by" into the FLWOR expression, rather than offering "sort" as a
free-standing function/operator as was done previously.

We propose that the functionality provided by the unordered() function be
offered instead by custom syntax in the FLWOR expressions: essentially by a
keyword UNORDERED which would be a syntactic alterative to the ORDER BY
clause.

Michael Kay
for Software AG