Major restructure of the module:

[lehins]

This is more of what I had in mind when I suggested the restructure.

• Separate System.Random into:
  • System.Random.Internal that hold most of the classes,
    internal functions and some of the instances
  • Sytstem.Random that export the pure interface only. That means
    RandomGen, Random, Uniform and UniformRange classes
  • System.Random.Monad all of the monadic functionality plus the
    re-export of the full System.Random module.
• Split the relevant parts of documentation into Pure and Monadic and
  place them into their corresponding modules

[curiousleo]

In #96, I decided not to export Uniform and UniformRange from System.Random because their definitions use MonadRandom:

class Uniform a where
  uniformM :: MonadRandom g s m => g s -> m a

In other words, in my understanding, Uniform and UniformRange as they are currently defined are part of the monadic interface, not part of the pure interface.

If a user only imports System.Random, it is not clear to me how they could use uniformM / uniformRM given that MonadRandom will not be in scope. Am I missing something here?

[lehins]

There are two functions exported couple lines above uniform and uniformR. They allow usage of instances of Uniform and UniformRange type classes with pure RandomGen while hiding the fact that it is done through the MonadRandom. Which is pretty neat I think ;)

But because definitions uniformM and uniformRangeM use MonadRandom for implementation, they are not exported from System.Random, so you are partially right.