music-pitch-literal-1.6: src/Data/Semigroup/Applicative.hs

module Data.Semigroup.Applicative where

import Control.Applicative
import Data.Semigroup

-- TODO move to semigroups package
instance Functor First where
    fmap f (First x) = First (f x)
instance Applicative First where
    pure x = First x
    First f <*> First x = First (f x)

instance Functor Last where
    fmap f (Last x) = Last (f x)
instance Applicative Last where
    pure x = Last x
    Last f <*> Last x = Last (f x)