{-# LANGUAGE FlexibleInstances #-}
module Test.Exhaustively where

import Control.Exception
import Control.Parallel.Strategies
import Data.Foldable

exhaustively :: Exhaustable i => i -> IO Bool
exhaustively = evaluate . exhaust

parExhaustively :: (Bounded i, Enum i, Exhaustable b) => (i -> b) -> IO Bool
parExhaustively f =
  evaluate $ foldl' seq True $
  withStrategy (parBuffer 1000 rseq) $
  map (exhaust . f) (enumFromTo minBound maxBound)

class Exhaustable i where
  exhaust :: i -> Bool

instance Exhaustable Bool where
  exhaust a = a `seq` a

instance (Bounded i, Enum i) => Exhaustable (i -> Bool) where
  exhaust f = foldl' seq True $ map f (enumFromTo minBound maxBound)