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sequence :: forall t a m. Traversable t => Applicative m => t (m a) -> m (t a)

sequence1 :: forall t b f. Traversable1 t => Apply f => t (f b) -> f (t b)

sequence1Default :: forall t a m. Traversable1 t => Apply m => t (m a) -> m (t a)

A default implementation of sequence1 using traverse1.

sequenceDefault :: forall t a m. Traversable t => Applicative m => t (m a) -> m (t a)

A default implementation of sequence using traverse.

distribute :: forall f a g. Distributive f => Functor g => g (f a) -> f (g a)

distributeDefault :: forall a f g. Distributive f => Functor g => g (f a) -> f (g a)

A default implementation of distribute, based on collect.

parSequence :: forall a t m f. Parallel f m => Applicative f => Traversable t => t (m a) -> m (t a)

sequence :: forall m p q a. Dissect p q => MonadRec m => p (m a) -> m (p a)

A tail-recursive sequence operation, implemented in terms of Dissect.

sequence :: forall c b a. HasApply b => HasMap b => HasTraverse a => HasPure b => a (b c) -> b (a c)

Sequences actions and collects the results.

sequence [Just 1, Just 2] -- Just [1, 2]

join :: forall a m. Bind m => m (m a) -> m a

Collapse two applications of a monadic type constructor into one.

optional :: forall f a. Alt f => Applicative f => f a -> f (Maybe a)

One or none.

optional empty = pure Nothing

The behaviour of optional (pure x) depends on whether the Alt instance satisfy the left catch law (pure a <|> b = pure a).

Either e does:

optional (Right x) = Right (Just x)

But Array does not:

optional [x] = [Just x, Nothing]

oneOf :: forall f g a. Foldable f => Plus g => f (g a) -> g a

Combines a collection of elements using the Alt operation.

genMaybe :: forall m a. MonadGen m => m a -> m (Maybe a)

Creates a generator that outputs Maybe values, choosing a value from another generator for the inner value. The generator has a 75% chance of returning a Just over a Nothing.

oneOf :: forall m f a. MonadGen m => Foldable1 f => f (m a) -> m a

Creates a generator that outputs a value chosen from a selection of existing generators with uniform probability.

parOneOf :: forall a t m f. Parallel f m => Alternative f => Foldable t => Functor t => t (m a) -> m a

Race a collection in parallel.

wrapFree :: forall f m a. MonadFree f m => f (m a) -> m a

keepLatest :: forall event a. IsEvent event => event (event a) -> event a

optional :: forall f a. Alt f => Applicative f => f a -> f (Maybe a)

keepLatest :: forall event a. IsEvent event => event (event a) -> event a

join :: forall v m c. HasBind c m => HasIdentity c => ObjectOf c (m v) => m (m v) -> m v

choice :: forall a g f. Foldable f => Alt g => Plus g => f (g a) -> g a

flatten :: forall b a. HasChain a => a (a b) -> a b

Removes a level of nesting from a container.

flatten [[1, 2], [3, 4]] -- [1, 2, 3, 4]

oneOf :: forall a m f. Foldable f => Alternative m => f (m a) -> m a

optionMaybe :: forall a m. Alternative m => m a -> m (Maybe a)

warbler :: forall m a. Bind m => m (m a) -> m a

W combinator - warbler - omega

MM

Λ a b . (a → a → b) → a → b

λ f x . f x x

integrateM :: forall a stM m base. Applicative base => MonadBaseControl base m stM => m (stM a) -> m a

Pack a state belonging to m back into it, instead of throwing it away

restoreM :: forall base m stM a. MonadBaseControl base m stM => base (stM a) -> m a

duplicate :: forall a w. Extend w => w a -> w (w a)

Duplicate a comonadic context.

duplicate is dual to Control.Bind.join.

fromMaybe :: forall f a. Unfoldable f => Maybe a -> f a

Convert a Maybe to any Unfoldable, such as lists or arrays.

fromMaybe (Nothing :: Maybe Int) == []
fromMaybe (Just 1) == [1]

unfoldable :: forall m f a. MonadRec m => MonadGen m => Unfoldable f => m a -> m (f a)

Creates a generator that produces unfoldable structures based on an existing generator for the elements.

The size of the unfoldable will be determined by the current size state for the generator. To generate an unfoldable structure of a particular size, use the resize function from the MonadGen class first.

unwrapCofree :: forall f w a. ComonadCofree f w => w a -> f (w a)

fork :: forall f m a. MonadFork f m => m a -> m (f a)

suspend :: forall f m a. MonadFork f m => m a -> m (f a)

toBase :: forall b m a. MonadUnlift b m => m a -> m (b a)

Run the given action inside the base monad b.

lift :: forall a g f. Applicative f => Applicative g => a -> f (g a)

split :: forall f a. Applicative f => f a -> f (f a)

pure :: forall f a. Applicative f => a -> f a

fromJust :: forall a. Partial => Maybe a -> a

A partial function that extracts the value from the Just data constructor. Passing Nothing to fromJust will throw an error at runtime.

forever :: forall m a b. MonadRec m => m a -> m b

forever runs an action indefinitely, using the MonadRec instance to ensure constant stack usage.

For example:

main = forever $ trace "Hello, World!"

singleton :: forall f a. Unfoldable1 f => a -> f a

Contain a single value. For example:

singleton "foo" == (NEL.singleton "foo" :: NEL.NonEmptyList String)

proof :: forall a b p. TypeEquals a b => p a -> p b

elements :: forall m f a. MonadGen m => Foldable1 f => f a -> m a

Creates a generator that outputs a value chosen from a selection with uniform probability.

downFrom :: forall a u. Enum a => Unfoldable u => a -> u a

Produces all predecessors of an Enum value, excluding the start value.

downFromIncluding :: forall a u. Enum a => Unfoldable1 u => a -> u a

Produces all predecessors of an Enum value, including the start value.

downFromIncluding top will return all values in an Enum, in reverse order.

upFrom :: forall a u. Enum a => Unfoldable u => a -> u a

Produces all successors of an Enum value, excluding the start value.

upFromIncluding :: forall a u. Enum a => Unfoldable1 u => a -> u a

Produces all successors of an Enum value, including the start value.

upFromIncluding bottom will return all values in an Enum.

coerce :: forall f a b. Contravariant f => Functor f => f a -> f b

throwError :: forall e m a. MonadThrow e m => e -> m a

inj :: forall f g a. Inject f g => f a -> g a

join :: forall f m a. MonadFork f m => f a -> m a