check_can_open_door

    This trigger will fire when an entity attempts to open a door or container.
    If the script deems that entity cannot open the door then it should present
    a message and return false. Since a return value is required, it is
    important to wrap the script in a protected block to ensure it runs to
    completion. The following variables are of interest for this trigger:

    @actor      - A pointer to the entity that is trying to open the door.

    @target     - A pointer to the target of the open action. This may be an
                  exit or an item.

    @direction  - If the @target is an exit, then this will be set to the
                  direction of the exit with respect to the room.

    @tool       - A pointer to an object that aided in the open action. For
                  instance when using a key to open a door, then this would be
                  a pointer to the associated key item.

    Your script must return a 1 or a 0 (or equivalent). Any value that does
    not evaluate to true, will prevent the @actor from completing the open
    action.