separate (Compilation_Unit.Produce_Metrics)
procedure Enumeration_Literal
             (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

    -- Enumeration_Literal ::= <IDENTIFIER> | <CHARACTER_LITERAL>

    Current_Token : Token_Package.Token;

begin
    -- Enumeration_Literal

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

    case Token_Package.Class_Of (Current_Token) is

        when Token_Package.Identifier =>

            -- increment Halstead operand count
            Halstead.Store_Operand (Halstead_Operand.Definition
                                       (Token_Package.Value_Of
                                           (This_Token => Current_Token)));

        when Token_Package.Character_Literal =>

            -- increment Halstead APOSTROPHES operator count
            Halstead.Store_Operator
               ((Kind => Halstead_Operator.Apostrophes_Halstead));

            -- increment Halstead operand count
            Halstead.Store_Operand (Halstead_Operand.Definition
                                       (Token_Package.Value_Of
                                           (This_Token => Current_Token)));

        when others =>
            raise Syntax_Error;

    end case;

end Enumeration_Literal;