M2compiler-V3/compiler/tests/t_classinherit.mod

MODULE TClassInherit;
(* Single inheritance: a child class inherits its parent's fields and
   methods; child method bodies see both (n from Base, m from Sub).
   Exit 7. *)
VAR ExitCode : INTEGER;
TYPE
  CLASS Base;
    n : INTEGER;
    PROCEDURE SetN(v : INTEGER);
    PROCEDURE GetN() : INTEGER;
  END Base;
  CLASS Sub (Base);
    m : INTEGER;
    PROCEDURE SetM(v : INTEGER);
    PROCEDURE Sum() : INTEGER;
  END Sub;
CLASS IMPLEMENTATION Base;
  PROCEDURE SetN(v : INTEGER);
  BEGIN n := v END SetN;
  PROCEDURE GetN() : INTEGER;
  BEGIN RETURN n END GetN;
END Base;
CLASS IMPLEMENTATION Sub;
  PROCEDURE SetM(v : INTEGER);
  BEGIN m := v END SetM;
  PROCEDURE Sum() : INTEGER;
  BEGIN RETURN n + m END Sum;
END Sub;
VAR s : Sub;
BEGIN
  s.SetN(3);          (* inherited method *)
  s.SetM(4);          (* own method, sets inherited+own fields *)
  ExitCode := s.Sum()
END TClassInherit.