defaultGamma :: Gamma //includes all default functions
defaultGamma = extend "print" (Forall ["a"] ((IdType "a") ->> VoidType))
- $ extend "isEmpty" (Forall ["a"] (ListType (IdType "a") ->> BoolType))
+ $ extend "isEmpty" (Forall ["a"] ((ListType (IdType "a")) ->> BoolType))
$ extend "read" (Forall [] (IntType ->> (ListType CharType)))
zero
generalize t = gamma >>= \g-> pure $ Forall (difference (ftv t) (ftv g)) t
lookup :: String -> Typing Type
-lookup "isEmpty" = ListType <$> fresh
lookup k = gamma >>= \g-> case 'Map'.member k g of
False = liftT (Left $ UndeclaredVariableError zero k)
True = instantiate $ 'Map'.find k g