Need help

[Nick Name]

On Wed, 24 Jul 2002 10:44:51 +0100 (BST)
"D. Tweed" <tweed@compsci.bristol.ac.uk> wrote:

> It wasn't clear to me whether Vincenzo's e-mail was saying that you
> just needed to be in IO to generate the seed or that you need to be in
> IO to do anything that involves generating random numbers __after
> you've got the seed__. Since I have to admit I really dislike having
> monads extend beyond the top couple of levels of a program I wanted to
> point out that actually generating and using random numbers can be
> done outside IO. 

Well, what I meant is that, being Haskell a lazy pure functional
language, the *right* way to use I/O and nondeterminism in general is
the IO monad. 

You can avoid it by using unsafeSomething but... it's unsafe. I like
haskell the way it is. 

If one wants to write pure code using a random number generator created
with newStdGen, which is in the IO monad, it's easy, he/she just writes
a pure function "f" whose argument is a random number generator. And
then the random number generator is created in the IO monad and "f" is
applied to it.

Vincenzo