INTERFACE {{p}}if_canteen_plan PUBLIC.
  TYPES ty_ingredient TYPE c LENGTH 10.
  TYPES ty_quantity TYPE p LENGTH 13 DECIMALS 3.

  TYPES:
    BEGIN OF ty_order,
      ingredient TYPE ty_ingredient,
      quantity   TYPE ty_quantity,
    END OF ty_order.
  TYPES tt_order TYPE STANDARD TABLE OF ty_order WITH EMPTY KEY.

  TYPES:
    BEGIN OF ty_master,
      ingredient TYPE ty_ingredient,
      pack_size  TYPE ty_quantity,
    END OF ty_master.
  TYPES tt_master TYPE STANDARD TABLE OF ty_master WITH EMPTY KEY.

  TYPES:
    BEGIN OF ty_pack,
      ingredient TYPE ty_ingredient,
      packs      TYPE i,
    END OF ty_pack.
  TYPES tt_pack TYPE STANDARD TABLE OF ty_pack WITH EMPTY KEY.

  TYPES tt_ingredient TYPE STANDARD TABLE OF ty_ingredient WITH EMPTY KEY.

  METHODS merge_orders
    IMPORTING it_orders_a      TYPE tt_order
              it_orders_b      TYPE tt_order
    RETURNING VALUE(rt_demand) TYPE tt_order.

  METHODS pack_requirement
    IMPORTING it_demand       TYPE tt_order
              it_catalogue    TYPE tt_master
    RETURNING VALUE(rt_packs) TYPE tt_pack.

  METHODS missing_ingredients
    IMPORTING it_demand        TYPE tt_order
              it_catalogue     TYPE tt_master
    RETURNING VALUE(rt_missing) TYPE tt_ingredient.
ENDINTERFACE.