{-# LANGUAGE TemplateHaskell #-} {-# LANGUAGE StandaloneDeriving #-} {-# LANGUAGE FlexibleInstances #-} module Main where import Data.CZipWith import Data.Functor.Identity import Data.Functor.Const data A f = A { a_str :: f String , a_bool :: f Bool } data B f = B { b_int :: f Int , b_float :: f Float , b_a :: A f } deriving instance Show (A Identity) deriving instance Eq (A Identity) deriving instance Eq (A (Const Bool)) deriving instance Eq (A Maybe) deriving instance Eq (B Identity) deriving instance Eq (B (Const Bool)) deriving instance Eq (B Maybe) deriveCZipWith ''A deriveCZipWith ''B deriveCPointed ''A deriveCPointed ''B deriveCZipWithM ''A deriveCZipWithM ''B main :: IO () main = do let x1 = B (Identity 12) (Identity 3.1) (A (Identity "string") (Identity True)) let x2 = B (Just 1) Nothing (A (Just "just") Nothing) let x3 = cZipWith (\x my -> case my of Nothing -> x Just y -> Identity y ) x1 x2 errorIf (x3 /= B (Identity 1) (Identity 3.1) (A (Identity "just") (Identity True)) ) \$ return () let (Identity x4) = cZipWithM (\x my -> Identity \$ case my of Nothing -> x Just y -> Identity y ) x1 x2 errorIf (x4 /= B (Identity 1) (Identity 3.1) (A (Identity "just") (Identity True)) ) \$ return () let (Identity x5) = cTraverse Identity x2 errorIf (x2 /= x5) \$ return () let x6 = cPoint (Const True) errorIf (x6 /= B (Const True) (Const True) (A (Const True) (Const True))) \$ return () putStrLn "no errors found!" errorIf :: Bool -> a -> a errorIf False = id errorIf True = error "errorIf"