小编old*_*123的帖子

我有三种数据类型:

data Person = Person { firstName :: String  
                     , lastName :: String  
                     , age :: Int  
                     , height :: Float  
                     , phoneNumber :: String  
                     , flavor :: String  
                     } deriving (Eq,Show, Read) 

data Car = Car {company :: String, model :: String, year :: Int} deriving (Eq,Show,Read)  

data Things = C Car | P Person deriving (Eq,Show,Read) 

我想在[[Things]]中找到Car的坐标.

我试过了:

enumerate = zip [0..]

findCar :: [[Things]] -> [(Int, Int)]
findCar things = do
        [(x, y)
          | (y, row) <- …