standardLib = Standard $ Map.fromList
                           [("put-line", StandardEntry { eSerialize = Cons (Label "native") (Cons (Label "put-line") Nil)
                                                       , eApply     = aPutLine
                                                       , eExecute   = ePutLine })
                           ,("get-line", StandardEntry { eSerialize = Cons (Label "native") (Cons (Label "get-line") Nil)
                                                       , eApply     = aGetLine
                                                       , eExecute   = eGetLine })]

aPutLine (m, x) = Cons (Label "put-line") x

ePutLine (m, Cons (Label x) Nil) = do putStrLn x
                                      return (m, Nil)
ePutLine (m, Cons (Label x) d)   = do putStrLn x
                                      ePutLine (m, d)
ePutLine (m, Nil)                = return (m, Nil)
ePutLine (m, b)                  = E.throw $ RuntimeException "type mismatch"

aGetLine (m, x) = Cons (Label "get-line") x

eGetLine (m, _) = do l <- getLine
                     return (m, Label l)