module SlowQueue where

------------------------------------------------------------------

empty   :: Q a
add     :: a -> Q a -> Q a
remove  :: Q a -> Q a
front   :: Q a -> a
isEmpty :: Q a -> Bool

------------------------------------------------------------------

data Q a = Q [a] deriving (Eq, Show)

empty             = Q []
add x (Q xs)      = Q (xs++[x])
remove (Q (x:xs)) = Q xs
front (Q (x:xs))  = x
isEmpty (Q xs)    = null xs

------------------------------------------------------------------