Ara - I found your question about the Pyparsing-based adventure game that I wrote. You can find more info on this from the presentation I made at PyCon'06, (http://www.python.org/pycon/2006/papers/4/). This link opens up at the title page, there are navigation controls in the lower right corner of the screen if you move your mouse over them.
This program uses the following classes: - Room - Item - Player - Command The Room and Item instances are created during the game setup. Each Room contains pointers to neighboring rooms to the north, south, east, and west. Rooms also have a list of items that are currently in the room. As the game ensues, items can be picked up and dropped, so this list will change over time. I guess you could change the room connections also - wouldn't be hard - perhaps as a result of using a special Item while in the Room. Items are fairly passive, free-standing objects, containing some attributes, and a possible useAction. They don't have much behavior, they don't know what room they are in, they can be picked up, dropped, and used, and they have a name that describes them when you look in a room, or list your player's inventory. Player is the "status" object of the game. Player has an inventory of Items, and has a reference to the Room the player is currently in. I think an easy mistake when writing a game is to make the Player status and attributes global variables. This will work okay, but by keeping this info in an object, the game could easily extend to having multiple players, just by adding a second instance, and adding support for the players to take turns giving commands. Command is the class that actually makes things happen. Command itself is an "abstract" class, that defines the basic form of what different commands can do, and how they are created. There are several subclasses of Command: - TakeCommand - DropCommand - InventoryCommand - UseCommand - LookCommand - DoorsCommand - MoveCommand - HelpCommand - QuitCommand Commands are created based on the input that the game player types in at the game prompt (this is where pyparsing comes in). The pyparsing grammar parses the input string, and if it is a valid command, the grammar's parse actions create the appropriate Command subclass. For instance, typing in "help" will create a HelpCommand instance. Typing in "take shovel" will create a TakeCommand, with the target object of "shovel". After the Command is created, it is executed against the Player object. The results of the Command can: - have the Player take something from the current Room - have the Player drop something in his inventory, and leave it in the current Room - list the Player's inventory - etc. The MoveCommand will move the player to an adjoining room. To tie it all together, the game engine runs in a basic loop: # create a player, let's call him Bob player = Player("Bob") # give Bob the sword for protection player.take( Item.items["sword"] ) # read commands, and then invoke them on Bob (and his surroundings) while not player.gameOver: cmdstr = raw_input(">> ") cmd = parser.parseCmd(cmdstr) if cmd is not None: cmd.command( player ) And that's it. All of the logic about the moving from room to room is captured in the N,S,E,W references between Room objects. Moving Bob from room to room is done by MoveCommands, as they are dynamically created based on user input. I hope that gives you a little more idea of how the pyparsing adventure game works. -- Paul _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor