|numb||The index of the base room to check from.|
With this function you can retrieve the index of the room
before the room input into the function. For example you can
use the read only variable room to get the index of the current room
and then use this function to find the room that comes before it in
the resource tree. If there is no room before the one you input
then -1 is returned.
if room_previous(room) != -1
The above code will check to see if the previous room exists and if so, it will go to it.