interface I
{
  in void e();
  out void a();
  out void hi();
  out void lo();

  behaviour
  {
    subint State {0..3};

    State state = 3;
    State c = 0;

    [true]
      on e:
      {
        if (state == 0 && state != 1)
        {
          state = 3;
          a;
        }
        else
        {
          state = state - 1;
          if (c < state)
          {
            c = c + 1;
          }
          else if (c >= state || c > state)
          {
            if (c <= (state + 1))
            {
              lo;
            }
            else
            {
              if (c > state)
              {
                hi;
              }
            }
          }
        }
      }
  }
}

component expressions
{
  provides I i;

  behaviour
  {
    subint State {0..3};

    State state = 3;
    State c = 0;

    [true]
      on i.e():
      {
        if (state == 0 && state != 1)
        {
          state = 3;
          i.a();
        }
        else
        {
          state = state - 1;
          if (c < state)
          {
            c = c + 1;
          }
          else
          {
            if (c <= (state + 1))
            {
              i.lo();
            }
            else if (c >= state || c > state)
            {
              if (c > state)
              {
                i.hi();
              }
            }
          }
        }
      }
  }
}