anchor.diff:      rbnx_n_af_inner*
   ;
   
  -// We break the inner commands for `router bgp neighbor address-family` into those can also be
  -// applied inside of DEFAULT (rbnx_n_af_common) and those that are only valid at the top level
  -// (default itself and inherit).
  +// We might get to this level of the hierarchy in four ways:
  +//  1. configuring an actual neighbor (router bgp ; (optional vrf) ; neighbor ; address-family)
  +//  2. configuring a template peer (router bgp ; template peer ; address-family)
  +//  3. configuring a template peer-policy (router bgp ; template peer-policy)
  +//  4. inside of DEFAULT command in any of the above 3 levels.
  +//     For now, DEFAULT is unhandled.
  +//
  +// All the remaining commands are valid at all levels 1-3.
   rbnx_n_af_inner
  -:
  -    rbnx_n_af_common
  -    | rbnx_n_af_default
  -    | rbnx_n_af_inherit
  -;
  -
  -rbnx_n_af_common
   :
       rbnx_n_af_advertise_map
       | rbnx_n_af_allowas_in
       | rbnx_n_af_as_override
       | rbnx_n_af_capability
  +    | rbnx_n_af_default
       | rbnx_n_af_default_originate
       | rbnx_n_af_disable_peer_as_check
       | rbnx_n_af_filter_list
  +    | rbnx_n_af_inherit
       | rbnx_n_af_maximum_prefix
       | rbnx_n_af_next_hop_self
       | rbnx_n_af_next_help_third_party
  
positive.code:     rbnx_n_inner*
  ;
  
  // We break the inner commands for `router bgp neighbor` into those can also be applied inside of
  // DEFAULT (rbnx_n_common) and those that are only valid at the top level (default itself and
  // inherit).
  rbnx_n_inner
  :
      rbnx_n_common
      | rbnx_n_default
      | rbnx_n_inherit
  ;
  
  rbnx_n_common
  :
      rbnx_n_address_family
      | rbnx_n_capability
      | rbnx_n_description
      | rbnx_n_disable_connected_check
      | rbnx_n_dont_capability_negotiate
      | rbnx_n_dynamic_capability
      | rbnx_n_ebgp_multihop
      | rbnx_n_local_as
      | rbnx_n_low_memory
      | rbnx_n_maximum_peers
  
negative.code: 
  rbnx_n_default
  :
      // TODO: implement default handling.
      DEFAULT null_rest_of_line
  ;
  
  rbnx_n_description
  