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Rational R1000/400 Tapes

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Index: B T

⟦4ba34a3d1⟧ TextFile

    Length: 2337 (0x921)
    Types: TextFile
    Names: »B«

Derivation

└─⟦180fe333a⟧ Bits:30000405 8mm tape, Rational 1000, SW CATALOG, 10_20_0
└─⟦180fe333a⟧ Bits:30000537 8mm tape, Rational 1000, SW Catalog 10_20_0
    └─⟦5cb1d1d7f⟧ »DATA« 
        └─⟦3b1ee7bd8⟧ 
            └─⟦this⟧

TextFile

separate (Token_Package)
procedure Peek (Next_Token : out Token) is

    Tail_Of_List : New_List.List;
    Location_Of_New_Token : New_List.List;
    Current_Token : Token;

begin
    -- Peek

    -- check if Peek_Token_Location is empty or not
    if New_List.Is_Equal (Peek_Token_Location, New_List.Null_List) then

        Build (New_Token => Current_Token,
               Previous_Token => Peek_Previous_Token);

        New_List.Construct (New_Item => Current_Token,
                            And_The_List => Location_Of_New_Token);

        if not New_List.Is_Equal (List_Of_Tokens, New_List.Null_List) then

            -- get tail of list
            New_List.Share (The_List => New_List.Tail_Of (List_Of_Tokens),
                            With_The_List => Tail_Of_List);

            -- append token at the end of list
            New_List.Append (This_List => Tail_Of_List,
                             And_This_List => Location_Of_New_Token);

        else
            -- list is EMPTY

            New_List.Share (The_List => Location_Of_New_Token,
                            With_The_List => List_Of_Tokens);

        end if;

        -- check if Next_Token_Location is null or not
        if New_List.Is_Equal (Next_Token_Location, New_List.Null_List) then

            -- if it is, assign Next_Token_Location to the
            -- head of List_Of_Tokens
            New_List.Share (The_List => List_Of_Tokens,
                            With_The_List => Next_Token_Location);

        end if;

    else
        -- Peek_Token_Location is not empty

        Guard_Against_Overflow:
            begin

                -- get next token from List_Of_Tokens
                Current_Token := New_List.Content_Of (Peek_Token_Location);

                -- advance Peek_Token_Location
                New_List.Share (The_List =>
                                   New_List.Seek (Peek_Token_Location, +1),
                                With_The_List => Peek_Token_Location);

            exception
                when New_List.Overflow =>
                    New_List.Share (The_List => New_List.Null_List,
                                    With_The_List => Peek_Token_Location);

            end Guard_Against_Overflow;

    end if;

    Peek_Previous_Token := Current_Token;
    Next_Token := Current_Token;

end Peek;