Please help!!!

What's wrong??

greatest common divisor from one list

code:



mdc :: Int-> Int -> Int
mdc _ 1 = 1
mdc 1 _ = 1
mdc x y
|x > y = mdc (x-y) y
|y > x = mdc (y-x) x
|x==y = x

mdcl :: [Int]-> [Int]
mdcl []=[]
mdcl l = mdcl ([mdc (tira(take 1 l)) (tira(take 1 (drop 1 l)))]++ drop 2 l)

gcdl :: [Int] -> Int
gcdl l = tira l

tira :: [Int] -> Int
tira []=0
tira [x]=x