Nullable

type Nullable = record

public

  property Value: T; [rw]

  property IsNull: Boolean; [r]

  property HasValue: Boolean; [r]

  property HasDefault: Boolean; [r]

  procedure ClearValue;

  procedure SetDefault();

  constructor Create();

  class operator implicit(T):();

  class operator implicit():T();

  class operator implicit(Pointer):();

  class operator explicit():T();

  class operator add(,):();

end;