有一些签名功能:
a -> IO (m b)
b -> IO (m c)
c -> IO (m d)
我如何将它们链接起来
a -> IO (m d)
？
实际应用:说有一组REST端点.返回值和下一个值都需要将previous返回的值作为参数.
因此从端点获取的函数如下:
Value1 -> IO (Maybe Value2)
Value2 -> IO (Maybe Value3)
Value3 -> IO (Maybe Value4)