// A probably needles optimization: convert the C string "just seen" to
// a C++ string just once, instead of twice every time a monster moves.
static const std::string _just_seen("just seen");

    if (monster->seen_context != "just seen")

    if (monster->seen_context != _just_seen)

    {
        // Give a message if we move back out of view.
        monster->seen_context = _just_seen;

    }

    // The only way to get closer to the player is to step out of view;
    // give a message so they player isn't confused about it being
    // announced coming into view but not being seen.
    monster->seen_context = _just_seen;

    // The monster gave a "comes into view" message and then immediately
    // moved back out of view, leaing the player nothing to see, so give
    // this message to avoid confusion.
    if (monster->seen_context == _just_seen && !see_grid(f))
        simple_monster_message(monster, " moves out of view.");