如何在Haskell中为网格创建坐标

Question

我试图定义一个函数grid :: Int -> [(Int,Int)]，它返回一个n×n方格上所有（x，y）坐标对的列表。

    grid :: Int -> [(Int,Int)]
    grid x y = [x y| |(x <- [1..x] y <- [1..y])]

GHCi告诉我

    parse error on input ‘<-’
    Perhaps this statement should be within a 'do' block?
Failed, modules loaded: none.
Prelude>

Answer 1

这是你想要做的吗？

 grid n = [(x, y)| x<- [0..n], y<-[0..n]]