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    Length: 3827 (0xef3)
    Types: TextFile
    Names: »B«

└─⟦a7d1ea751⟧ Bits:30000550 8mm tape, Rational 1000, !users!projects 94_04_11
    └─⟦129cab021⟧ »DATA« 
        └─⟦this⟧ 

TextFile

with Bounded_String;
with Error_Broadcaster;
with Lex;
with Object;
with Value;  
with Bloc_Class;
with Unparser;
package body Expression is
    type Node_Structure is
        record
            Rule : Natural range 0 .. 1 := 0;
            Val : Value.Node := Value.Empty_Node;
            Ident : Object.Message;
        end record;

    procedure Parse (N : in out Node; Error : out Boolean) is
        Failed : Boolean := False;
        Ident_Error : Object.Message;
    begin
        N := new Node_Structure;
        Bounded_String.Copy (Ident_Error, Lex.Get_Value);
        if Value.Is_First (Lex.Get_Token) then
            N.Rule := 0;
            Value.Parse (N.Val, Failed);
        else  
            case Lex.Get_Token is
                when Lex.Pour =>  
                    N.Rule := 1;
                    Lex.Next_Token;
                    case Lex.Get_Token is
                        when Lex.Identifier =>  
                            Bounded_String.Copy (N.Ident, Lex.Get_Value);
                            Bloc_Class.Put (N.Ident);
                            Lex.Next_Token;
                            case Lex.Get_Token is
                                when Lex.Prendre =>  
                                    Lex.Next_Token;
                                    if Value.Is_First (Lex.Get_Token) then
                                        Value.Parse (N.Val, Failed);  
                                    else
                                        raise Error_Broadcaster.
                                                 Unexpected_Token;  
                                    end if;
                                when others =>
                                    raise Error_Broadcaster.Prendre_Is_Missing;
                            end case;
                        when others =>
                            Failed := True;
                            raise Error_Broadcaster.Identifier_Is_Missing;
                    end case;
                when others =>
                    Failed := True;
                    Error_Broadcaster.Unexpectedtoken (Lex.Get_Line);
                    raise Error_Broadcaster.Expression_Is_Missing;
            end case;
        end if;
        Error := Failed;
    exception
        when Error_Broadcaster.Pour_Is_Missing =>
            Error_Broadcaster.Pour_Missing (Lex.Get_Line);
            N.Rule := 1;
            Bounded_String.Copy (N.Ident, Ident_Error);
            Bloc_Class.Put (N.Ident);
            Lex.Next_Token;
            Value.Parse (N.Val, Failed);
            Error := Failed;
        when Error_Broadcaster.Prendre_Is_Missing =>  
            Error_Broadcaster.Prendre_Missing (Lex.Get_Line);
            Value.Parse (N.Val, Failed);
            Error := Failed;  
    end Parse;

    procedure Unparse (N : Node) is
    begin
        case N.Rule is
            when 0 =>
                Value.Unparse (N.Val);

            when 1 =>
                Unparser.Put ("pour ");  
                Unparser.Put (Bounded_String.Image (N.Ident));
                Unparser.Put (" prendre ");
                Value.Unparse (N.Val);
        end case;
    end Unparse;


    function Is_First (T : Lex.Token) return Boolean is
        use Lex;
    begin
        return T = Lex.Pour or else Value.Is_First (T);

    end Is_First;

    function Interpret (N : Node;
                        Inherited : Object.Reference := Object.Void_Reference)
                       return Object.Reference is
        Result : Object.Reference;
    begin
        case N.Rule is
            when 0 =>
                Result := Value.Interpret (N.Val);
            when 1 =>
                Result := Value.Interpret (N.Val);
                Bloc_Class.Set (N.Ident, Result);
        end case;
        return Result;
    end Interpret;
end Expression;