如何打印不帶小數點的小數點x當且僅當x是積分？

Question

在Haskell中如何打印不帶小數點的小數x當且僅當x是積分？請改善我的代碼如下：

printFrac :: (Show a, RealFrac a) => a -> IO() 
printFrac x = if x==fromIntegral (round x) then print (round x) else print x 

Answer 1

以下情況如何？

printFrac :: (Show a, RealFrac a) => a -> IO() 
printFrac x 
    | a == 0 = print b 
    | otherwise = print x 
    where (b, a) = properFraction x 

測試：

λ> printFrac 1.0 
1 
λ> printFrac 1.1 
1.1 
λ> printFrac 1 
1