[Tutor] define vars by iteration

[Luke Jordan]

Thanks for this insight into classes. It often takes me a few days to absorb
and respond because my job limits the time I can give to programming. But
thanks again for taking the time to respond in a meaningful way.
 I guess I could say that you changed my world when it comes to programming
(sorry, low-hanging fruit :))
 Luke

 On 10/20/05, Danny Yoo <dyoo at hkn.eecs.berkeley.edu> wrote:
>
>
>
> > Also, I have done what I'm trying to do successfully by populating a
> > dictionary with class instances named after self.name <http://self.name><
> http://self.name>,
> > which, after the function runs, I can access this way
> > >>> classDictionary["Yard"]
> > <class instance>
> > the thing is I would like to be able to get at Yard's attributes by
> typing
> > >>> Yard.anAttribute
> > garbage cans
> > at the prompt rather than
> > >>> Yard = classDictionary["Yard"]
> > >>> Yard.anAttribute
> > garbage cans
>
>
> Hi Luke,
>
> One thing to note is that we can formally plunk and embed these places in
> some kind of World:
>
> ######################################################
> class World:
> def __init__(self):
> self.places = {}
> def attach(self, place):
> """Given a place, attaches it to the world."""
> self.places[place.name <http://place.name>] = place
> def lookup(self, name):
> return self.places[name]
> ######################################################
>
>
> If each place was aware that it was a part of a world --- that is, if we
> embed the World inside each place as a part of a place's state --- then
> things might work out.
>
> For example, we might have a north-south corridor:
>
> ##################################################################
> class Corridor:
> def __init__(self, world, name, northName, southName):
> self.world, self.name <http://self.name>, self.northName, self.southName =
> (
> world, name, northName, southName)
> def N(self):
> return self.world.lookup(self.northName)
> def S(self):
> return self.world.lookup(self.southName)
> ##################################################################
>
> What's a little funny about this Corridor definition is that, because a
> cooridor knows its in the world, it can also ask the world what place
> 'northName' stands for in its N() method.
>
>
> Here's a small test:
>
> ######
> >>> world = World()
> >>> world.attach(Corridor(world, "Water cooler",
> ... north="Stairs", south="Boss Office"))
> >>> world.attach(Corridor(world, "Stairs",
> ... north="Wall", south="Water cooler"))
> >>>
> >>>
> >>> world.lookup("Water cooler")
> <__main__.Corridor instance at 0x403a7fcc>
> >>> world.lookup("Water cooler").name
> 'Water cooler'
> >>> world.lookup("Water cooler").N()
> <__main__.Corridor instance at 0x403a7f6c>
> >>> world.lookup("Water cooler").N().name
> 'Stairs'
> ######
>
> Another advantage of having a central place is that saving and restoring
> the environment is just a matter of pickling the world. Hmmm... briny
> pickles... *grin* Sorry, I'm getting distracted by food.
>
>
> Does this make sense? Please feel free to ask more questions.
>
>
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