Zemyla

import Control.Comonad
import Data.Functor

newtype Select r a = Select { runSelect :: (a -> r) -> a }

instance Functor (Select r) where
  fmap f s = Select $ \p -> f $ runSelect s $ p . f

instance Applicative (Select r) where
  pure a = Select $ const a

Zemyla

{-# LANGUAGE RankNTypes, MagicHash, UnboxedTuples #-}

module TraverseArray (runSTArray, runSTUArray, traverseArray) where

import qualified GHC.Exts as E
import GHC.Exts (State#, Array#, MutableArray#, Int#, Int(..), isTrue#)
import Control.Applicative (Applicative(..))
import qualified Data.Array.Base as A
import Data.Array.Base (UArray(..), STUArray(..))
import GHC.Arr (Array(..), STArray(..))