Random number generation : requirements

The W3C WGs are looking at the idea of introducing a random-number function of
some kind in XPath 3.1. The challenge of course is making this both usable and
a pure function with no side-effects. We have various design ideas which we
need to test against requirements.

If you have any applications that use or need such a function, please could I
have a brief description of the way it uses random numbers, e.g. just wanting
a single random number, a random permutation of 52 integers, an arbitrary
sequence of random numebrs for test data generation, etc.

If you're currently using the EXSLT random-sequence() function, please share
your experience with it.

Michael Kay
Saxonica