separate (Compilation_Unit.Produce_Metrics)
procedure Null_Statement
             (Current_Compilation_Unit : in out Ada_Compilation_Unit;
              Program_Unit : in Program_Unit_State_Machine;
              Halstead : in Halstead_State_Machine;
              Loc : in Loc_State_Machine;
              Mccabe : in Mccabe_State_Machine) is

    --=====================================================
    -- NULL_Statement ::= "NULL" ";"
    --=====================================================

    Current_Token : Token_Package.Token;

begin
    -- NULL_Statement

    Get_Next_Token (Out_Token => Current_Token,
                    From => Current_Compilation_Unit,
                    Current_Loc => Loc);

    if "/=" (Token_Package.Value_Of (Current_Token),
             Token_Package.Null_Token) then
        raise Syntax_Error;
    end if;

    -- increment Halstead NULL operator count
    Halstead.Store_Operator ((Kind => Halstead_Operator.Null_Halstead));

    Get_Next_Token (Out_Token => Current_Token,
                    From => Current_Compilation_Unit,
                    Current_Loc => Loc);

    if "/=" (Token_Package.Value_Of (Current_Token),
             Token_Package.Semicolon_Token) then
        raise Syntax_Error;
    end if;

    -- increment Halstead SEMICOLON operator count
    Halstead.Store_Operator ((Kind => Halstead_Operator.Semicolon_Halstead));

end Null_Statement;