{-# OPTIONS -XTemplateHaskell -XMultiParamTypeClasses #-}
import UpdatableViewStub 

{-# LINE 4 "../examples/queue.hs" #-}
data Q a = None 
         | More a (Q a) deriving (Show, Eq) 

{-# LINE 21 "../examples/queue.hs" #-}
data Qi a = Qi [a] [a] deriving (Show, Eq) 

instance UpdatableView (Qi a ) (Q a ) where 
{-# LINE 33 "../examples/queue.hs" #-}
    view = $(foldT ''Qi) ( (idB <**> reverseB) >>>> appendB) >>>> l2l 
          where l2l = $(foldT ''[]) ( $(toC 'None) <||> $(toC 'More) )


isEmpty :: Q a -> Bool 
isEmpty None = True 
emptyQ :: Q a 
emptyQ = None
enQ :: a -> Q a -> Q a 
enQ = 
  let
    enQ a (Qi x y) = Qi x (a:y)
  in (toView :: (a -> Qi a -> Qi a ) ->  (a -> Q a -> Q a )) enQ
deQ :: Q a -> Q a
deQ = 
  let
    deQ (Qi (a:x) y) = Qi x y
    deQ (Qi [] y)    = deQ (Qi (reverse y) [])
  in (toView :: (Qi a -> Qi a) ->  (Q a -> Q a)) deQ
first :: Q a -> a  
first = 
  let
    first (Qi (a:x) y) = a 
    first (Qi [] y)    = first (Qi (reverse y) [])
  in (toView :: (Qi a -> a ) ->  (Q a -> a  )) first
{-# LINE 36 "../examples/queue.hs" #-}
mapQ f None       = None 
mapQ f (More a x) = More (f a) (mapQ f x)

play1 0     q = first q 
play1 (n+1) q = do hd 
                   play1 n (enQ hd tl)
   where hd = first q 
         tl = deQ   q