Re: Trivial Haskell Concurrency problem

[George Russell]

Marcin 'Qrczak' Kowalczyk wrote:
> If the IO monad can maintain a random number generator, it can as
> well mainain unique Integer supply. The interface is clean.
It can, but according to the current specification, it doesn't.  Maybe
it should.  I think Integer is a little too specific - how about

type Unique implements (Ord,Eq)
newUnique :: IO Unique

?
> 
> And what about having unsafePtrCompare in addition to IOExts.unsafePtrEq?
I don't think unsafePtrCompare will get us out of jail here.  Compacting
garbage collection might change the order of the pointers around inbetween
one thread comparing them and the other.