如何比較列表中的兩個元組？

Question

我有這樣的元組列表：

[(0.0,0.0),(1.0,0.0),(2.0,0.0),(3.0,0.0),(3.0,0.0),(3.0,0.0),(4.0,0.0),(4.0,0.0)]

其中第一個元素是X坐標，第二個元素是Y坐標，我現在想編寫將返回的函數：

[(0.0,0.0),(1.0,0.0),(2.0,0.0),(3.0,0.0),(3.0,1.0),(3.0,2.0),(4.0,0.0),(4.0,1.0)]

它從第一個元組中取出第一個元素，從第二個元組中取出第一個元素，如果它們不相等，則Y不變，但如果它們相等，則將Y加一個。

如果有人有想法如何在Haskell中寫作？

Answer 1

尚未測試，但可以執行以下操作：

foo :: [(Float, Float)] -> [(Float, Float)]
foo []  = []
foo [x] = [x]
foo ((xx, xy):(yx, yy):xs) = (xx, xy): theTuple : (foo ((yx, yy):xs))
    where
        theTuple = if xx == yx then (yx, yy) else (yx, yy+1)