[Python-Dev] properties on modules?

2003年1月13日 12:30:47 -0800

Skip Montanaro wrote:
> I think the question is still open whether or not modules should
> be able to support properties, though I do think the ball is back in his
> court to come up with a less contrived example.

The Quixote web system publishes Python functions by traversing name
spaces. The publishing code is very roughly:
 def get_object(container, name):
 if hasattr(container, name):
 return getattr(container, name)
 elif isinstance(container, ModuleType):
 mname = container.__name__ + '.' + name
 __import__(mname)
 return sys.modules[mname]
 else:
 raise TraversalError
 def publish(path):
 o = root_namespace
 for component in '/'.split(path[1:]):
 o = get_object(o, component)
 return o()
If you use instances for name spaces then you can use __getattr__ or
properties to lazily create attributes. It's annoying that there is
nothing like __getattr__/__setattr__ or properties for modules. 
 Neil