Class decorators do not inherit properly

Bruno Desthuilliers bruno.42.desthuilliers at
Fri Jul 13 09:37:31 CEST 2007

Lee Harr a écrit :
>> Traceback (most recent call last):
>>   File "/Users/chris/Projects/CMR/", line 132, in <module>
>>     class M0(MetropolisHastings):
>>   File "/Users/chris/Projects/CMR/", line 173, in M0
>>     @_add_to_post
>> NameError: name '_add_to_post' is not defined
>> yet, when I look at the dict of the subclass (here called M0), I see the 
>> decorator method:
> I think the term "class decorator" is going to eventually
> mean something other than what you are doing here. I'd
> avoid the term for now.
> When you decorate a class method,
> the function you use
> needs to be defined before the method definition.

This is true whatever you are decorating - class method, static method, 
instance method, function. And FWIW, the term "class method" has a 
definite meaning in Python.

> Using a class method to decorate another class method is
> going to be tricky. The way I usually do it is to create
> a separate function outside of the class definition for
> the decorator function.

The problem is then that this function cannot easily access the class 
object - which is what the OP want.

> You're going to have to show us the actual code you are
> having trouble with, or else (probably more useful, really)
> try to put together a minimal example of what you are
> trying to do and show us that code.

+1 on this

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