peekArg :: Peg Value
peekArg = do PegState s (x:a) w n c b p <- get
             return x
peekArg :: Peg Value
peekArg = do PegState s (x:a) w n c b p <- get
             return x
peekArg = do PegState s (x:a) w n c b p <- get
             return x