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program tformin8;
// Test IEnumerable and IEnumerator in the for-in loop
{$mode objfpc}{$H+}
{$APPTYPE CONSOLE}
type
{ TMyListEnumerator }
TMyListEnumerator = class(TInterfacedObject, IEnumerator)
private
FCurrent: Pointer;
function GetCurrent: TObject;
public
function MoveNext: Boolean;
procedure Reset;
property Current: TObject read GetCurrent;
end;
TMyList = class(TInterfacedObject, IEnumerable)
public
function GetEnumerator: IEnumerator;
end;
{ TMyListEnumerator }
function TMyListEnumerator.GetCurrent: TObject;
begin
Result := TObject(FCurrent);
end;
function TMyListEnumerator.MoveNext: Boolean;
begin
inc(PByte(FCurrent));
Result := FCurrent <= Pointer(3);
end;
procedure TMyListEnumerator.Reset;
begin
FCurrent := nil;
end;
{ TMyList }
function TMyList.GetEnumerator: IEnumerator;
begin
Result := TMyListEnumerator.Create;
end;
var
List: IEnumerable;
i: TObject;
begin
List := TMyList.Create;
for i in List do
WriteLn(PtrUInt(i));
List := nil;
end.
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