[Python-Dev] Re: PEP 318: Can't we all just get along?

[Paul Morrow]

James Y Knight wrote:

> On Aug 19, 2004, at 7:45 AM, Paul Morrow wrote:
> 
>> The vast majority of instance methods I've seen all use 'self' as the 
>> first parameter.  Likewise, most class methods use 'cls' or 'klass' as 
>> their first parameter.  If we exploit these conventions, we end up 
>> with a simple, clear, obvious mechanism for denoting (this aspect of) 
>> a method's type.
>>
>>     class Foo(Object):
>>         def m1(self, a, b):    # this is an instance method of Foo
>>             pass
>>
>>         def m2(cls, a, b):     # this is a class method of Foo
>>             pass
>>
>>         def m3(a, b):          # this is a static method of Foo
>>             pass
>>
>> A special Object (capital 'O') class could work this magic so that old 
>> code didn't break.
>>
>> I know that this is odd.  But then so are most of the great things 
>> about Python.
> 
> 
> You can do that today. See also 
> http://www.python.org/pycon/dc2004/papers/48/conveniencytypes.py
> 

Aha!  Thanks!

> However, note that IMO it is quite rude to use a metaclass (or your 
> capital O object -- same thing) to do this, as it will break any objects 
> inheriting from your class that don't expect the strange automatic 
> behavior. This auto-class/staticmethod-ification should be local to your 
> code, and thus is really a candidate for a class decorator.
> 
> @automethods
> class Foo(object):
>   ...
> 

But then wouldn't subclasses of Foo have the same rude behavior?  In 
fact, isn't the use of any metaclass rude, by your definition, as it 
will change the default class behavior in some way?