AFAICS it is safe provided.. f always returns the same value for a given argument list and.. f has no observable side effects.
What are called "side effects" ?
It looks to me like what you're trying to do is run three parallel evaluation algorithms and take the answer from whichever one delivers an answer first (via the MVar, which should be empty initially).
Yes, thats what im trying to do
f1,f2,f3 all deliver the same answer (if they deliver an answer at all) and that answer depends on nothing but xs and none of them have any observable side effects then I guess you're probably safe.
depends on value of the first two elements of the list, f1, f2 and f3 will return three different values. So is it safe ? _________________________________________________________________ Winks & nudges are here - download MSN Messenger 7.0 today! http://messenger.msn.co.uk