相关疑难解决方法(0)

为什么类型(+).(+)IS (Num a, Num (a -> a)) => a -> (a -> a) -> a -> a？

(+) :: Num a => a -> a -> a
(.) :: (b -> c) -> (a -> b) -> a -> c

我曾尝试过，但不知道结果如何(Num a, Num (a -> a)) => a -> (a -> a) -> a -> a。

(+) :: Num i => i -> i -> i
(.) :: (b -> c) -> (a -> b) …