descriptors for container items

[Brock Filer]

... or something like that.

I have an XMLish data structure whose nodes'  __get/set/del item__ 
methods resolve as:

node['foo'] -> node.children['foo']
node['@bar'] -> node.attributes['bar']

so you can say:

countries['us']['Colorado']['Denver']['@population']

This is going to be used in user-input formulae, so I'm willing to do a 
lot of work for minor beautifications. I'd like to be able to say (I 
know, the quotes are still ugly, but at least you save a bracket):

countries/'us'/'Colorado'/'Denver'/'@population'

That's easy to do with a __div__ method, but it only works for getting, 
not setting or deleting.

I'd appreciate any thoughts on this problem. I keep thinking 
descriptors might be involved somehow in the solution, but I may be on 
a completely wrong track.