/* all - teste alle ableitungen */
struct
a
end;

method b(c d)
  var e := 0;
  c := e;
  d = e;
  if (e = d) then c := 1-2; end;
  if (e < d) then c := 1 or 2 or 3; else c := c * d * e; end;
  while (not d) do
     d := d.c - d -d - d;
     d.c := c.d - d.c;
     b (d, c);
     b.b (c, d);
  end;
  return c = d;
end;