Data.Const

newtype Const a b

The Const type constructor, which wraps its first type argument and ignores its second. That is, Const a b is isomorphic to a for any b.

Const has some useful instances. For example, the Applicative instance allows us to collect results using a Monoid while ignoring return values.

Constructors

• Const a

Instances

• Newtype (Const a b) _
• (Eq a) => Eq (Const a b)
• (Eq a) => Eq1 (Const a)
• (Ord a) => Ord (Const a b)
• (Ord a) => Ord1 (Const a)
• (Bounded a) => Bounded (Const a b)
• (Show a) => Show (Const a b)
• Semigroupoid Const
• (Semigroup a) => Semigroup (Const a b)
• (Monoid a) => Monoid (Const a b)
• (Semiring a) => Semiring (Const a b)
• (Ring a) => Ring (Const a b)
• (EuclideanRing a) => EuclideanRing (Const a b)
• (CommutativeRing a) => CommutativeRing (Const a b)
• (HeytingAlgebra a) => HeytingAlgebra (Const a b)
• (BooleanAlgebra a) => BooleanAlgebra (Const a b)
• Functor (Const a)
• Invariant (Const a)
• Contravariant (Const a)
• (Semigroup a) => Apply (Const a)
• (Monoid a) => Applicative (Const a)
• Foldable (Const a)
• Traversable (Const a)