On Wed, Aug 31, 2011 at 5:41 AM, Steven D'Aprano <steve@pearwood.info>wrote:
To make it work using just ordinary assignment syntax, as you suggest, requires more than just an "alias" function. It would need changes to the Python internals. Possibly very large changes. Without a convincing use-case, I don't think that will happen.
Well, once you clear up some of the ambiguities in the request, it's not quite so bad. class F(object): def m(self): alias(a, b) Which name space is a being aliased in? Function local? Instance? Class? Module? So alias needs to take a namespace of some sort. The appropriate object is easy to find, and should do the trick (though function local might be entertaining). For simplicity, we'll assume that aliases have to be in the same namespace (though doing otherwise isn't really harder, just slower). Passing in variable values doesn't work very well - especially for the new alias, which may not *have* a value yet! For the name to be aliased, you could in theory look up the value in the namespace and use the corresponding name, but there may be more than one of those. So pass that one in as a string as well. So make the call "alias(o, name1, name2)". o is a module, class, instance, or function. Name lookups are done via the __dict__ dict for all of those. It's easy to write a dict subclass that aliases it's entries. So the internal changes would be making __dict__ a writable attribute on any objects which it currently isn't, and making sure that the various objects use __setitem__ to change attribute values. I suspect the performance hit - even if you don't use this feature - would be noticeable. If you used it, it would be even worse. -1. <mike