anchor.diff:     | vlan_tagging_if_stanza
   ;
   
  -aggregated_ether_options_if_stanza
  -:
  -   AGGREGATED_ETHER_OPTIONS ignored_substanza
  -;
  -
  -description_if_stanza
  -:
  -   description_common_stanza
  -;
  -
  -encapsulation_if_stanza
  -:
  -   encapsulation_common_stanza
  -;
  -
  -framing_if_stanza
  -:
  -   FRAMING ignored_substanza
  -;
  -
  -flexible_vlan_tagging_if_stanza
  -:
  -   FLEXIBLE_VLAN_TAGGING SEMICOLON
  -;
  -
  -gigether_options_if_stanza
  -:
  -   GIGETHER_OPTIONS ignored_substanza
  -;
  -
  -link_mode_if_stanza
  -:
  -   LINK_MODE VARIABLE SEMICOLON
  -;
  -
  -mac_if_stanza
  -:
  -// TODO [p1]: should be MAC_ADDRESS, solve with lexer modes in antlr 4
  -   x = MAC y = MAC_ADDRESS SEMICOLON
  -;
  -
  -mtu_if_stanza
  -:
  -   mstr = mtu_common_stanza
  +null_u_if_stanza
  +:
  +   description_u_if_stanza
  +   | encapsulation_u_if_stanza
  +   | input_vlan_map_u_if_stanza
  +   | output_vlan_map_u_if_stanza
  +   | tunnel_u_if_stanza
  +   | vlan_tags_u_if_stanza
  +;
  +
  +output_vlan_map_u_if_stanza // TODO [Ask Ari]: probably not supposed to ignore this
  +
  +:
  +   OUTPUT_VLAN_MAP VARIABLE SEMICOLON
  +;
  +
  +policer_fam_u_if_stanza
  +:
  +   POLICER ignored_substanza
  +;
  +
  +port_mode_fam_u_if_stanza // TODO [P0]: should not be ignored
  +
  +:
  +   PORT_MODE VARIABLE
  +;
  +
  +primary_fam_u_if_stanza
  +:
  +   PRIMARY SEMICOLON
  +;
  +
  +rpf_check_fam_u_if_stanza
  +:
  +   RPF_CHECK FAIL_FILTER? URPF_LOGGING? SEMICOLON
  +;
  +
  +targeted_broadcast_fam_u_if_stanza
  +:
  +   TARGETED_BROADCAST SEMICOLON
   ;
   
   traps_if_stanza
  
positive.code:    | null_u_if_stanza
  ;
  
  apply_groups_u_if_stanza // TODO: FIX!
  
  :
     apply_groups_stanza
  ;
  
  disable_u_if_stanza
  :
     DISABLE SEMICOLON
  ;
  
  enable_u_if_stanza
  :
     ENABLE SEMICOLON
  ;
  
  family_u_if_stanza
  :
     FAMILY
     (
        ft = BRIDGE
        | ft = CCC
        | ft = INET
        | ft = INET_VPN
        | ft = INET6
        | ft = INET6_VPN
        | ft = ISO
        | ft = L2_VPN
        | ft = ETHERNET_SWITCHING
        | ft = MPLS
        | ft = VPLS
     )
     (
        SEMICOLON
        |
        (
           OPEN_BRACE fam_u_if_stanza_list CLOSE_BRACE
        )
     )
  ;
  
  vlanid_u_if_stanza
  :
     VLAN_ID DEC SEMICOLON
  ;
  
  null_u_if_stanza
  :
     description_u_if_stanza
     | encapsulation_u_if_stanza
     | input_vlan_map_u_if_stanza
     | output_vlan_map_u_if_stanza
     | tunnel_u_if_stanza
     | vlan_tags_u_if_stanza
  ;
  
  description_u_if_stanza
  :
     description_common_stanza
  ;
  
  encapsulation_u_if_stanza
  :
     encapsulation_common_stanza
  ;
  
  input_vlan_map_u_if_stanza // TODO [Ask Ari]: probably not supposed to ignore this
  
  :
     INPUT_VLAN_MAP ignored_substanza
  ;
  
  output_vlan_map_u_if_stanza // TODO [Ask Ari]: probably not supposed to ignore this
  
  :
     OUTPUT_VLAN_MAP VARIABLE SEMICOLON
  ;
  
  tunnel_u_if_stanza // TODO [Ask Ari]: probably not supposed to ignore this
  
  :
     TUNNEL ignored_substanza
  ;
  
  vlan_tags_u_if_stanza // TODO [Ask Ari]: probably not supposed to ignore this
  
negative.code:    | apply_groups_if_stanza
  ;
  
  if_stanza_list
  :
     (
        if_stanza
        | inactive_if_stanza
     )+
  ;
  
  inactive_fam_u_if_stanza
  :
     INACTIVE COLON fam_u_if_stanza
  ;
  
  inactive_if_stanza
  :
     INACTIVE COLON if_stanza
  ;
  
  inactive_interface_stanza
  :
     INACTIVE COLON interface_stanza
  ;
  
  inactive_u_if_stanza
  :
     INACTIVE COLON u_if_stanza
  ;
  
  input_vlan_map_u_if_stanza // TODO [Ask Ari]: probably not supposed to ignore this
  
  :
     INPUT_VLAN_MAP ignored_substanza
  ;
  
  interface_mode_fam_u_if_stanza // TODO [P0]: should not be ignored
  
  :
     INTERFACE_MODE ACCESS SEMICOLON
  ;
  
  interface_stanza
  :
     name = VARIABLE? OPEN_BRACE if_stanza_list CLOSE_BRACE
  ;
  
  interfaces_stanza
  :
     INTERFACES OPEN_BRACE
     (
        interface_stanza
        | inactive_interface_stanza
     )+ CLOSE_BRACE
  ;
  
  link_mode_if_stanza
  :
     LINK_MODE VARIABLE SEMICOLON
  ;
  
  mac_if_stanza
  :
  // TODO [p1]: should be MAC_ADDRESS, solve with lexer modes in antlr 4
     x = MAC y = MAC_ADDRESS SEMICOLON
  ;
  
  mtu_fam_u_if_stanza
  :
     mtu_common_stanza
  ;
  
  mtu_if_stanza
  :
     mstr = mtu_common_stanza
  ;
  
  native_vlan_id_fam_u_if_stanza
  :
     NATIVE_VLAN_ID DEC SEMICOLON
  ;
  
  no_neighbor_learn_fam_u_if_stanza
  :
     NO_NEIGHBOR_LEARN SEMICOLON
  ;
  
  no_redirects_fam_u_if_stanza
  :
     NO_REDIRECTS SEMICOLON
  ;
  
  null_fam_u_if_stanza
  :
     interface_mode_fam_u_if_stanza
     | mtu_fam_u_if_stanza
     | port_mode_fam_u_if_stanza
     | no_redirects_fam_u_if_stanza
     | no_neighbor_learn_fam_u_if_stanza
     | policer_fam_u_if_stanza
     | primary_fam_u_if_stanza
     | rpf_check_fam_u_if_stanza
     | targeted_broadcast_fam_u_if_stanza
     | vlan_id_fam_u_if_stanza
  ;
  
  null_if_stanza
  