Code:

---

define vector_x,skill20;
define vector_y,skill21;
define vector_z,skill22;

var test_vec[3] = 5,10,15;

action entity_act
{
  vec_set(my.vector_x,test_vec);
//  ...
  my.vector_z += 30;
}

---

All code above is example code and should run with no errors.