Module

Data.Unfoldable.Trivial.Internal

Package: purescript-trivial-unfold
Repository: UnrelatedString/purescript-trivial-unfold

This module provides the Trivial type as an existentially quantified dumb wrapper around unfold, which can be inspected and manipulated to implement various typeclasses and the utilities in Data.Unfoldable.Trivial.

This module also contains the implementations of utilities which rely on directly inspecting Trivial values and are re-exported by Data.Unfoldable.Trivial. Use this module directly only if you intend to directly inspect Trivial values yourself.

#Trivial Source

newtype Trivial a

A type wrapping unfoldr calls, existentially quantified over the seed type so that it can be ignored in the type constructor. Its Unfoldable instance means that it can directly be constructed by calling unfoldr.

Instances

Unfoldable Trivial
Wraps both arguments to unfoldr in an UnfoldrCall.
Unfoldable1 Trivial
Functor Trivial
Foldable Trivial
The raison d'être for Trivial. Allows folding polymorphic Unfoldables as they generate.

foldr uses a default implementation and may be inefficient. Note also that this enables the use of sequence_ despite the lack of a Traversable instance, which is not provided because it would require forcing and accumulating every value, at which point any would-be user is better off with an actual container.
(Arbitrary a, Coarbitrary a) => Arbitrary (Trivial a)
Guaranteed finite.
Lazy (Trivial a)

#Generator Source

type Generator a b = b -> Maybe (a /\ b)

Alias for the generator function passed to unfoldr.

#trivial Source

trivial :: forall a. Trivial a -> Trivial a

Specializes its argument to Trivial.

#untrivial Source

untrivial :: forall a c. (forall b. Generator a b -> b -> c) -> Trivial a -> c

Convenience function for inspecting Trivial values. Calls the function argument on the contents of the inner Exists.

#turbofish Source

turbofish :: forall a b. (Trivial a -> b) -> Trivial a -> b

Function application specialized to a Trivial argument, at the same precedence as ($).

Inspired by the Rust syntax of the same name, often used in the analogous context of collecting from an iterator.

#(::<*>) Source

Operator alias for Data.Unfoldable.Trivial.Internal.turbofish (right-associative / precedence 0)

#unfoldr1Default Source

unfoldr1Default :: forall a b t. Unfoldable t => (b -> a /\ (Maybe b)) -> b -> t a

Provides a default implementation of unfoldr1 using unfoldr to satisfy the superclass bound on Unfoldable.

#runTrivial Source

runTrivial :: forall a u. Unfoldable u => Trivial a -> u a

Converts to any other Unfoldable. Can also be seen as evaluating the inner UnfoldrCall.

This is only useful in implementing utility functions. In all other cases, simply use the desired type directly.

Modules: Data.Unfoldable.MaybeEmpty; Data.Unfoldable.Trivial; Data.Unfoldable.Trivial.Internal; Data.Unfoldable1.Trivial1; Data.Unfoldable1.Trivial1.Internal