module crossproduct
import StdEnv
($) infixr 1;($) a b :== a b;(>>=) infixl 0;(>>=) a b = \ w -> (\ (x, w) -> b x w ) (a w);liftM m :== \ lst -> \ w ->  (m lst, w);
join del [x:xs]= (toString x) +++ del +++ (join del xs);
join _ [] = "";
:: Elem= ElemChar Char | ElemStr String | ElemInt Int
class toElem a  where
    toElem :: a -> Elem
instance toElem Int where
    toElem a = ElemInt a
instance toElem Char where
    toElem a = ElemChar a
instance toElem String where
    toElem a = ElemStr a
instance toString Elem where
    toString (ElemInt a) = toString a
    toString (ElemStr a) = a
    toString (ElemChar a) = toString a
Start w =snd ((stdio >>= liftM ( fwrites str) >>= fclose) w)
    where str = join "\n" $ map (join ",") $ crossProduct [] elems2
          elems2 = [map toElem [0,1],map toElem ['ab'], map toElem ["Foo","Bar"]]
crossProduct :: [Elem] [[Elem]] -> [[Elem]]
crossProduct knil [[x:xs]:ys] = crossProduct [x:knil] ys ++ (crossProduct knil [xs:ys])
crossProduct knil [[]:ys] =  []
crossProduct knil [] =  [knil]