[Haskell-cafe] rand* why not of type State g a
zednenem at psualum.com
Sat Aug 19 19:09:07 EDT 2006
Henning Thielemann writes:
> On Sun, 13 Aug 2006, Marc Weber wrote:
> > the rand* function are examples for a typical state usage, arent'
> > Is there any reasoon why they are not defined
> > RandomGen g => State g a
> > rather than
> > RandomGen g => (a,a) -> g -> (a,g)
> > ?
> It's probably because Control.Monad.State belongs to the MTL which is
> outside Prelude.
On the other hand, if you are using MTL, you'd probably want a more
general signature, like:
(RandomGen g, MonadState g m) => m a
David Menendez <zednenem at psualum.com> | "In this house, we obey the laws
<http://www.eyrie.org/~zednenem> | of thermodynamics!"
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