Foundation.Random

This module deals with the random subsystem abstractions.

It provide 2 different set of abstractions:

• The first abstraction that allow a monad to generate random through the MonadRandom class.
• The second abstraction to make generic random generator RandomGen and a small State monad like wrapper MonadRandomState to abstract a generator.

Documentation

class (Functor m, Applicative m, Monad m) => MonadRandom m where

A monad constraint that allows to generate random bytes

Minimal complete definition

getRandomBytes

Methods

getRandomBytes :: CountOf Word8 -> m (UArray Word8)

Instances

MonadRandom IO

Methods

getRandomBytes :: CountOf Word8 -> IO (UArray Word8)

RandomGen gen => MonadRandom (MonadRandomState gen)

Methods

getRandomBytes :: CountOf Word8 -> MonadRandomState gen (UArray Word8)

newtype MonadRandomState gen a

A simple Monad class very similar to a State Monad with the state being a RandomGenerator.

Constructors

MonadRandomState

Fields

• runRandomState :: gen -> (a, gen)

Instances

Monad (MonadRandomState gen)

Methods

(>>=) :: MonadRandomState gen a -> (a -> MonadRandomState gen b) -> MonadRandomState gen b

(>>) :: MonadRandomState gen a -> MonadRandomState gen b -> MonadRandomState gen b

return :: a -> MonadRandomState gen a

fail :: String -> MonadRandomState gen a

Functor (MonadRandomState gen)

Methods

fmap :: (a -> b) -> MonadRandomState gen a -> MonadRandomState gen b

(<$) :: a -> MonadRandomState gen b -> MonadRandomState gen a

Applicative (MonadRandomState gen)

Methods

pure :: a -> MonadRandomState gen a

(<*>) :: MonadRandomState gen (a -> b) -> MonadRandomState gen a -> MonadRandomState gen b

(*>) :: MonadRandomState gen a -> MonadRandomState gen b -> MonadRandomState gen b

(<*) :: MonadRandomState gen a -> MonadRandomState gen b -> MonadRandomState gen a

RandomGen gen => MonadRandom (MonadRandomState gen)

Methods

getRandomBytes :: CountOf Word8 -> MonadRandomState gen (UArray Word8)

class RandomGen gen where

A Deterministic Random Generator (DRG) class

Minimal complete definition

randomNew, randomNewFrom, randomGenerate

Methods

randomNew :: MonadRandom m => m gen

Initialize a new random generator

randomNewFrom :: UArray Word8 -> Maybe gen

Initialize a new random generator from a binary seed.

If Nothing is returned, then the data is not acceptable for creating a new random generator.

randomGenerate :: CountOf Word8 -> gen -> (UArray Word8, gen)

Generate N bytes of randomness from a DRG

Instances

RandomGen RNGv1

Methods

randomNew :: MonadRandom m => m RNGv1

randomNewFrom :: UArray Word8 -> Maybe RNGv1

randomGenerate :: CountOf Word8 -> RNGv1 -> (UArray Word8, RNGv1)

getRandomPrimType :: forall randomly ty. (PrimType ty, MonadRandom randomly) => randomly ty

withRandomGenerator :: RandomGen gen => gen -> MonadRandomState gen a -> (a, gen)

Run a pure computation with a Random Generator in the MonadRandomState

type RNG = RNGv1

An alias to the default choice of deterministic random number generator

Unless, you want to have the stability of a specific random number generator, e.g. for tests purpose, it's recommended to use this alias so that you would keep up to date with possible bugfixes, or change of algorithms.

data RNGv1

RNG based on ChaCha core.

The algorithm is identical to the arc4random found in recent BSDs, namely a ChaCha core provide 64 bytes of random from 32 bytes of key.

Instances

RandomGen RNGv1

Methods

randomNew :: MonadRandom m => m RNGv1

randomNewFrom :: UArray Word8 -> Maybe RNGv1

randomGenerate :: CountOf Word8 -> RNGv1 -> (UArray Word8, RNGv1)