I was thinking about the dynamic behavior of par, and there's something that's a little confusing to me. Am I right in understanding that (x `par` y) evaluates to y, and may or may not evaluate x along the way? I think it would be easier to reason about if we knew that x would be evaluated, either by a newly-spawned thread or by the parent thread. If I'm understanding this correctly, this could be done by defining x `pSeq` y = x `par` y `seq` x `seq` y (seq has higher precedence than par) When (x `pSeq` y) is evaluated, x may or may not be evaluated by a new thread. The parent thread continues along evaluating y. Then the parent makes sure x was evaluated before finally returning y. I've not seen this approach used before -- Is there something I'm missing that makes using pSeq as above just silly? Thanks! Chad Scherrer Computational Mathematics Group Pacific Northwest National Laboratory "Time flies like an arrow; fruit flies like a banana." -- Groucho Marx