On 10/19/2010 1:46 PM, Ian Kelly wrote:
On Tue, Oct 19, 2010 at 5:37 AM, Dave Angel <da...@ieee.org <mailto:da...@ieee.org>> wrote:On 2:59 PM, dex wrote: Using strong references, I have to remove room B from list of rooms, and also remove door to room B, as it holds reference to room B. To do that, I have to keep list of doors that lead to room B. Using weak references, I don't have to worry about removing all doors to room B. They all now have a dead reference, which better models actual situation. If part of mine collapses, or if a module on space station is destroyed, the passage to that location does not magically vanish - it's just obstructed. Can you please tell me if there's something wrong with my reasoning? Simply replace room B with a "destroyed room" object. That can be quite small, and you only need one, regardless of how many rooms are thus eliminated. How does this avoid the problem of having to keep a list of doors that lead to room B? You can't just replace one object with another. You would have to replace every reference to B with a reference to the new object. This is no simpler than deleting the references or replacing them with None.
One should rather *change* (not replace) the room into a 'destroyed room' or 'collapsed passage' or whatever, that cannot be entered. The keeps the room around but allows it to be repaired, rebuilt, cleared, or whatever.
-- Terry Jan Reedy -- http://mail.python.org/mailman/listinfo/python-list
