e bkwd_state0;         typedef typename apply0< BackwardOp, bkwd_state0, typename deref<iter0>::type >::type bkwd_state0;         typedef typename apply0< BackwardOp, bkwd_state0, typename deref<iter0>::type >::type bkwd_state0;         typedef typename apply0< BackwardOp, bkwd_state0, typename deref<iter0>::type >::type bkwd_state0;         typedef typename apply0< BackwardOp, bkwd_state0, typename deref<iter0>::type >::type bkwd_state0;                   typedef bkwd_state0 state;         typedef 