Zachary Pincus wrote: > Hi folks, > > I'm sure this has come up before, but the search terms I've been using > are so non-specific that I can't get any traction on Google. > > Here's my question: > I have written a subclass of ModuleType that handles lazy loading of > some slow resources. I would like a given module to be created as an > instance of that particular subclass on import, so that if I do: > > import foo > type(foo) > > I get <type 'myModule'> instead of <type 'module'>. > > Is there any way to effect this? Something like __metaclass__ = ... but > at the beginning of a module instead of at the beginning of a class?
Would be interesting to know about the motivation. Is foo just your own module or "any" module. * you can replace __import__ * you can set sys.modules['foo']=mymod (in sitecustomize.py ? ) * your module can be a class instance as well in newer pythons (2.2+?); => you can set sys.modules['foo']=Foo() # Foo having properties ... * simply import certain expensive modules only ad-hoc * maybe you don't need it as module at all, but an instance. or you avoid pre-computing things in global namespace. ... robert --- PS: In the Python standard lib there are some slow importing monsters. The worst is now urllib2 needing up to a second to import. Thats because there is a questionable style of importing all kind of expensive stuff that _might_ be useful in advance as if we had C-style compiler #include-s. Yet Python allows best-amongst-most-programming-languages dynamic modularization of code by local/late imports. Most time you'll see, that the imported modules are anyway only needed in very few locations. the pychecker helps. See rejected: http://sourceforge.net/tracker/index.php?func=detail&aid=1053150&group_id=5470&atid=305470 Meanwhile the cookielib is also amongst those urllib2 inhabitants - and its the slowest towards my profile runs. I've regular private patches on my production python installation to get apps (startup) fluid. Maybe that rejected sf request should be re-opened, and a request put to optimize the python lib for late dynamic import's - at least in locations where (regardign a profiler inspection) it pays off well on low coding costs ? -- http://mail.python.org/mailman/listinfo/python-list
