Safe Haskell | None |
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Most of the code is borrowed from a mailing list discussion. Therefor, credits go to Paul Johnson and Felix Martini.

- newtype GenT m a = GenT {}
- runGenT :: GenT m a -> Gen (m a)
- class (Applicative g, Monad g) => MonadGen g where
- var :: Integral n => n -> StdGen -> StdGen
- suchThat :: MonadGen m => m a -> (a -> Bool) -> m a
- suchThatMaybe :: MonadGen m => m a -> (a -> Bool) -> m (Maybe a)
- listOf :: MonadGen m => m a -> m [a]
- listOf1 :: MonadGen m => m a -> m [a]
- vectorOf :: MonadGen m => Int -> m a -> m [a]
- oneof :: MonadGen m => [m a] -> m a
- frequency :: MonadGen m => [(Int, m a)] -> m a
- elements :: MonadGen m => [a] -> m a
- growingElements :: MonadGen m => [a] -> m a
- oneofMay :: MonadGen m => [m a] -> m (Maybe a)
- elementsMay :: MonadGen m => [a] -> m (Maybe a)
- growingElementsMay :: MonadGen m => [a] -> m (Maybe a)

# Documentation

class (Applicative g, Monad g) => MonadGen g whereSource

var :: Integral n => n -> StdGen -> StdGenSource

Private variant-generating function. Converts an integer into a chain of (fst . split) and (snd . split) applications. Every integer (including negative ones) will give rise to a different random number generator in log2 n steps.

## Common generator combinators

suchThat :: MonadGen m => m a -> (a -> Bool) -> m aSource

Generates a value that satisfies a predicate.

suchThatMaybe :: MonadGen m => m a -> (a -> Bool) -> m (Maybe a)Source

Tries to generate a value that satisfies a predicate.

listOf :: MonadGen m => m a -> m [a]Source

Generates a list of random length. The maximum length depends on the size parameter.

listOf1 :: MonadGen m => m a -> m [a]Source

Generates a non-empty list of random length. The maximum length depends on the size parameter.

# Partial functions

oneof :: MonadGen m => [m a] -> m aSource

Randomly uses one of the given generators. The input list must be non-empty.

frequency :: MonadGen m => [(Int, m a)] -> m aSource

Chooses one of the given generators, with a weighted random distribution. The input list must be non-empty.

elements :: MonadGen m => [a] -> m aSource

Generates one of the given values. The input list must be non-empty.

growingElements :: MonadGen m => [a] -> m aSource

Takes a list of elements of increasing size, and chooses among an initial segment of the list. The size of this initial segment increases with the size parameter. The input list must be non-empty.

# Non-partial functions resulting in Maybe

elementsMay :: MonadGen m => [a] -> m (Maybe a)Source

Generates one of the given values.

growingElementsMay :: MonadGen m => [a] -> m (Maybe a)Source

Takes a list of elements of increasing size, and chooses among an initial segment of the list. The size of this initial segment increases with the size parameter.