UnionsAsRecAndVV.purs

-- Row-type records as variants and variants as records

-- type Either a b = (left :: a | right :: b)
type Either a b = 
  forall r . { left :: a -> r, right :: b -> r} -> r

-- type Pair a b = forall r . (fst :: a->r | snd :: b->r) -> r
type PairHelper a b = 
  forall r . { fst :: a -> r, snd :: b -> r } -> r
type Pair a b = 
  forall r . PairHelper (a -> r) (b -> r) -> r

eitherEx :: Either Int Boolean
eitherEx k = k.left 1

eitherEx2 :: Int
eitherEx2 = eitherEx { left: id, right: \x -> if x then 0 else 1 }

pairEx :: Pair String Int
pairEx k = k { fst: \j -> j "foo", snd: \j -> j 23 }

pairEx1 :: String
pairEx1 = pairEx (\x -> x.fst id)

pairEx2 :: Int
pairEx2 = pairEx (\x -> x.snd id)