pushArg x = modify (\(PegState s a w n c b p) -> PegState s (x:a) w n c b p)
pushArg x = modify (\(PegState s a w n c b p) -> PegState s (x:a) w n c b p)
pushArg x = modify (\(PegState s a w n c b p) -> PegState s (x:a) w n c b p)