gcc/testsuite/algol68/execute/formula-5.a68

{ This tests that names are passed properly to monadic operators. }

begin mode Foo = struct (int i,j);
      Foo f;
      i'f := 10;
      j'f := 20;
      op + = (ref Foo f) int: (i'f +:= 2; j'f +:= 2; i'f + j'f);
      assert (+f = 34);
      assert (i'f = 12);
      assert (j'f = 22)
end