我嘗試在Haskell中創建一個函數來顯示列表的元素,但它不起作用。我做錯了什麼?Haskell簡單顯示列表程序的元素
showw :: [Int a]=> [a] -> b
showw []=0
showw (x:xs)= x ++ showw xs
它給我這個錯誤:
aplicatie.hs:1:12: error:
• Expected a constraint, but ‘[Int a]’ has kind ‘*’
• In the type signature: afisare :: [Int a] => [a] -> b
aplicatie.hs:1:13: error:
• Expecting one fewer argument to ‘Int’ Expected kind ‘* -> *’, but
‘Int’ has kind ‘*’
• In the type signature: afisare :: [Int a] => [a] -> b
它是如何工作的? –
它給了我這個錯誤: aplicatie.hs:1:12:error: •預期的約束,但'[Int a]'有'*' •在簽名類型中: afisare :: [Int a ] => [a] - > b aplicatie.hs:1:13:error: •期望減少一個參數到'Int' 預期種類'* - > *',但是'Int'具有種類'*' •在簽名類型中: afisare :: [Int a] => [a] - > b –
您應該將其添加到問題中。 – Cirdec