模式Haskell中的解析錯誤

Question

爲什麼在此代碼中出現分析錯誤？

data One = H| I deriving (Read,Show,Eq) 
data E = A | B deriving (Read,Show,Eq) 
type L = [E] 

fun1 :: One -> E -> One 
-- function for fun1 is here 

fun2 :: One -> L -> One 
fun2 a [] = a 
fun2 a x:xs = fun2 (fun1 a x) xs --<<< I am getting error here 

Answer 1

嘗試：

fun2 a (x:xs) = fun2 (fun1 a x) xs