Pelmen wrote: > >>> class Test: > def __getattr__(self, attr): > print attr > > def foo(x): > print x > > >>> t = Test() > >>> print t > __str__ > > Traceback (most recent call last): > File "<pyshell#23>", line 1, in -toplevel- > print t > TypeError: 'NoneType' object is not callable > > what i have to do? define __str__ explicitly?
By seemingly not returning anything your __getattr__() method actually returns None. Instead you should raise an AttributeError when your __getattr__() encounters the name of an attribute it doesn't handle. Let's assume Test.__getattr__() should implement an attribute 'alpha' and nothing else: >>> class Test: ... def __getattr__(self, name): ... print "looking up", name ... if name == "alpha": ... return 42 ... print "lookup failed for", name ... raise AttributeError ... >>> print Test() looking up __str__ lookup failed for __str__ looking up __repr__ lookup failed for __repr__ <__main__.Test instance at 0x4029248c> When the lookup fails in the instance it is deferred to the class. By the way, new-style classes handle __special__ methods a bit differently -- try deriving Test from object class Test(object): # same as above to see the difference. Peter -- http://mail.python.org/mailman/listinfo/python-list
