function enemy_event
{
  if( event_type == event_detect ) // I detected an entity with c_scan
  {
    if( your == player ) // the entity I detected is "player"
    {
      wait(1);
      c_trace( my.x, player.x, ignore_passable+ignore_me ); // trace a line to "player"
      if( your == player ) // the object hit by c_trace is the player (not a wall, other entity, etc.)
      {
        beep; // signify that I have seen the player
        my.flag1 = on; // so I don't "beep" again
      }
    }
  }
}

action enemy
{
  my.enable_detect = on; // so I can see the player
  my.event = enemy_event;

  while(my) // while I exist
  {
    if( my.flag1 == off ) // I haven't seen the player yet
    {
      c_scan( my.x, my.pan, vector( 160, 0, 2000 ), ignore_me+scan_ents ); // scan for the player
    }

    wait(1);
  }
}