module Language.DTC.Utils where

import Control.Applicative (Applicative(..))
import Data.Eq (Eq)
import Data.Function (($), (.))
import Data.Functor (Functor(..), (<$>))
import Text.Show (Show)

-- * Type 'PaddedList'
data PaddedList a
 =   PaddedList { padded :: [a]
                , padder :: a
                } deriving (Eq, Show)

instance Functor PaddedList where
	fmap = (<*>) . pure
instance Applicative PaddedList where
	pure = PaddedList []
	PaddedList xs x <*> PaddedList ys y =
		zapp xs ys `PaddedList` x y
		where
		zapp [] bs = x <$> bs
		zapp as [] = ($ y) <$> as
		zapp (a : as) (b : bs) = a b : zapp as bs