相关疑难解决方法(0)

Haskell Data.Bifunctor基本上是:

class Bifunctor f where
  bimap :: (a -> c) -> (b -> d) -> f a b -> f c d 

我也能找到一个Biapply.我的问题是,为什么不存在完整的双层次结构(层次结构？),如:

class Bifunctor f => Biapplicative f where
  bipure :: a -> b -> f a b
  biap :: f (a -> b) (c -> d) -> f a c -> f b d 

class Biapplicative m => Bimonad m where
  bibind :: m a b -> (a -> b -> m c d) …