From: Leslie Viljoen <leslie@...>
Date: 2005-11-28T05:57:27+09:00
Subject: Object access heirarchies

I often have this problem in my projects.

I have a bunch of classes to do various things in my program, but
once instantiated they each need access to each other. For example,
in the adventure game I am working on, I have a Parser object that
needs to manipulate a Player, Map and Things in the map.

I normally do such things by passing objects around when initializing,
like so:

parser = Parser(Player.new(World.new(Map.new, Things.new)))

That works, although it seems a little long winded - for the
parser to modify a thing, it needs to set something like:
player.world.thing["ball"].name = "bat"

Later, the Things needed access to the Map so I could set thing.location
to a map.room object. So I changed thing.location to be a string --
thing.location_name and made a function that could look up a location
based on it's name: map["garden"].

What I want to know is: what's the best way? I had globals $player, 
$world, $map
earlier and that makes things a bit easier but it also makes me nervous
(perhaps just because I have been anti-global-indoctrinated for 20 years 
now)
I'm still a bit vague on Modules. Any ideas?

Les