On 29/12/2011 20:39, Jerzy Karczmarczuk wrote:

Still, I dont understand what does S.H. mean by a "perfectly good pure generator".
Tell more please (unless you just mean a stream, say:

Probably bad wording, to be honest. I only meant that there's random number handling support in the Haskell library and, and least judging by type signatures, it's pure functional code with no hint of the IO monad.

AFAIK there's no hidden unsafePerformIO sneaking any entropy in behind the scenes. Even if there was, it might be a legitimate reason for unsafePerformIO - random numbers are in principle non-deterministic, not determined by the current state of the outside world and which-you-evaluate-first should be irrelevant. If you have a quantum genuine-random-numbers gadget, the IO monad might be considered redundant for functions that get values from it - though it still isn't referentially transparent as it returns a different value each time even with the same parameters.