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    Types: TextFile
    Names: »B«

└─⟦5829e5ed5⟧ Bits:30000534 8mm tape, Rational 1000, RCI 2_0_5
    └─⟦c9a165082⟧ »DATA« 
        └─⟦2162db02b⟧ 
            └─⟦this⟧ 

TextFile

package body Stack_Generic is

    type Stack_Node is
        record
            Elt : Element;
            Link : Stack;
        end record;

    procedure Make_Empty (S : in out Stack) is
    begin
        S := null;
    end Make_Empty;

    procedure Pop (S : in out Stack) is
    begin
        if S = null then
            raise Underflow;
        else
            S := S.Link;
        end if;
    end Pop;


    procedure Push (X : Element; S : in out Stack) is
        New_Node : Stack;
    begin
        New_Node := new Stack_Node'(Elt => X, Link => S);
        S := New_Node;
    end Push;


    function Empty (S : Stack) return Boolean is
    begin
        return S = null;
    end Empty;


    function Top (S : Stack) return Element is
    begin
        if S = null then
            raise Underflow;
        else
            return S.Elt;
        end if;
    end Top;

    procedure Copy (Target : in out Stack; Source : Stack) is
        Rest_Of_Source : Stack;
        Last_Of_Target : Stack;
    begin
        if Source /= null then
            Target := new Stack_Node'(Elt => Source.Elt, Link => null);

            Last_Of_Target := Target;
            Rest_Of_Source := Source.Link;
            while Rest_Of_Source /= null loop
                Last_Of_Target.Link :=
                   new Stack_Node'(Elt => Rest_Of_Source.Elt, Link => null);
                Last_Of_Target := Last_Of_Target.Link;
                Rest_Of_Source := Rest_Of_Source.Link;
            end loop;
        else
            Target := null;
        end if;
    end Copy;

    procedure Init (Iter : out Iterator; S : Stack) is
    begin
        Iter := Iterator (S);
    end Init;

    procedure Next (Iter : in out Iterator) is
    begin
        Iter := Iterator (Iter.Link);
    end Next;

    function Value (Iter : Iterator) return Element is
    begin
        return Iter.Elt;
    end Value;

    function Done (Iter : Iterator) return Boolean is
    begin
        return Iter = null;
    end Done;

end Stack_Generic;