[Python-Dev] Re: __metaclass__ and __author__ are already decorators

[Bob Ippolito]

On Aug 21, 2004, at 6:24 PM, Paul Morrow wrote:

> Bob Ippolito wrote:
>
>> On Aug 21, 2004, at 5:34 PM, Paul Morrow wrote:
>>> Phillip J. Eby wrote:
>>>
>>>> At 05:15 PM 8/21/04 -0400, Paul Morrow wrote:
>>>>
>>>>> Christophe Cavalaria wrote:
>>>>>
>>>>>> can it be ? There's also the fact that it can't handle named 
>>>>>> parameters
>>>>>> like a regular function call. You can't write that :
>>>>>> def foo():
>>>>>>     __decoration__ = (1,1,param=True)
>>>>>
>>>>>
>>>>>
>>>>> As far as I know, we can't do that with the current decorator 
>>>>> proposals either.
>>>>
>>>> @decoration(1,1,param=True)
>>>> def foo(whatever):
>>>>     pass
>>>
>>>
>>> Ok, then whatever changes you've made to the Python system to 
>>> support that would allow the same syntax to be used in what I'm 
>>> suggesting.
>>>
>>>     def foo(whatever):
>>>         __decoration__ = (1,1,param=True)
>>>
>>>     def decoration(decoratedFunc, a, b, param=False):
>>>         __decorator__ = True
>>>         __version__ = '0.1'
>>>         # body of 'decoration' decorator function goes here...
>> Congratulations, this by far the worst suggestion yet!  I'm -Inf on 
>> this :)
>
> Thanks.
>
>
>> @decoration(1,1,param=True) makes no changes whatsoever to the Python 
>> system.  Everything after the @ is really just an expression.  The @ 
>> just implies that the result of the next class or def gets put 
>> through the result of the @expression before it is thrown into the 
>> namespace.
>
> It seems that writing a decorator is going to be a bizarre experience. 
> In the example, I would need to write a function named 'decoration' 
> that returns a function that will recieve a function (foo) to be 
> decorated and then return a function.  Does that sound about right?

Yes that is correct.

> What would functions like 'decoration' typically look like?  Could you 
> show a short code snippet?

http://python.org/peps/pep-0318.html

-bob