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{-# LANGUAGE CPP #-}
{-# LANGUAGE DeriveFunctor #-}
{-# LANGUAGE EmptyDataDecls #-}
{-# LANGUAGE StandaloneDeriving #-}
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE TypeFamilies #-}
#if __GLASGOW_HASKELL__ >= 702
{-# LANGUAGE DeriveGeneric #-}
#endif
-----------------------------------------------------------------------------
-- |
-- Module : GenericSpec
-- Copyright : (C) 2011-2016 Edward Kmett
-- License : BSD-style (see the file LICENSE)
--
-- Maintainer : Edward Kmett <ekmett@gmail.com>
-- Stability : provisional
--
-- Tests for generically derived 'Distributive' instances.
----------------------------------------------------------------------------
module GenericsSpec (main, spec) where
import Test.Hspec
#if __GLASGOW_HASKELL__ >= 702
import Data.Distributive (Distributive(..))
import Data.Distributive.Generic (genericCollect, genericDistribute)
# if __GLASGOW_HASKELL__ >= 706
import Generics.Deriving.Base hiding (Rep)
# else
import qualified Generics.Deriving.TH as Generics (deriveAll1)
# endif
#endif
main :: IO ()
main = hspec spec
spec :: Spec
#if __GLASGOW_HASKELL__ < 702
spec = return ()
#else
spec = do
describe "Id" $
it "distribute idExample = idExample" $
distribute idExample `shouldBe` idExample
describe "Stream" $
it "runId (shead (stail (distribute streamExample))) = 1" $
runId (shead (stail (distribute streamExample))) `shouldBe` 1
describe "PolyRec" $
it "runId (plast (runId (pinit (distribute polyRecExample)))) = 1" $
runId (plast (runId (pinit (distribute polyRecExample)))) `shouldBe` 1
newtype Id a = Id { runId :: a }
deriving (Eq, Functor, Show)
instance Distributive Id where
collect = genericCollect
distribute = genericDistribute
idExample :: Id (Id Int)
idExample = Id (Id 42)
data Stream a = (:>) { shead :: a, stail :: Stream a }
deriving Functor
instance Distributive Stream where
collect = genericCollect
distribute = genericDistribute
streamExample :: Id (Stream Int)
streamExample = Id $ let s = 0 :> fmap (+1) s in s
data PolyRec a = PolyRec { pinit :: Id (PolyRec a), plast :: a }
deriving Functor
instance Distributive PolyRec where
collect = genericCollect
distribute = genericDistribute
polyRecExample :: Id (PolyRec Int)
polyRecExample = Id $ let p = PolyRec (Id $ fmap (+1) p) 0 in p
# if __GLASGOW_HASKELL__ >= 706
deriving instance Generic1 Id
deriving instance Generic1 Stream
deriving instance Generic1 PolyRec
# else
$(Generics.deriveAll1 ''Id)
$(Generics.deriveAll1 ''Stream)
$(Generics.deriveAll1 ''PolyRec)
# endif
#endif
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