Re: [boost] [next gen future-promise] What to call themonadicreturntype?

Seems to me that future and promise both first need to take their spinlock and then the other's, which creates the potential for deadlock.

You could fix that by preallocating a sufficiently big static array of spinlocks, then generating an index when creating the promise and using spinlock_[i] in both. Collisions are possible but harmless. This non-allocating implementation is an interesting argument in favor of the current "unique future", which I've long disliked. I prefer futures to be shared_futures. That may too be possible to implement without allocation, but it's kind of complicated.