[Python-Dev] Class decorators (original) (raw)

Phillip J. Eby pje at telecommunity.com
Fri Mar 31 18:52:05 CEST 2006

At 04:47 AM 3/31/2006 -0800, Michael Chermside wrote:

In the discussion over class decorators, Jim Jewett writes: > I have often started with a function, and ended up replacing it with a > callable object so that I could save state without resorting to > "defalt args" or worse. > > I would prefer to decorate these exactly like the functions they replace.

I have observed the entire discussion about class decorators with absolutely no opinion, until I read Jim's brief post quoted above. I am now completely convinced that class decorators ought to exist and behave exactly like function decorators. Thanks, Jim for pointing out what should have been obvious to me from the start. The ability to use callable objects as functions is a powerful tool in Python, and ought not be broken by decorator inconsistencies.

Unless the class has a metaclass implementing call, or you mean that you want instance creation to be a call, I don't understand what you mean.

Nonetheless, the discussion has only been about where the decorators go and what syntax they use. Nobody has proposed any change in decorator semantics, so please stop attacking this meaningless strawman.

Moving from:

 @foo
 def bar(...):
     ...

to:

 class bar:
     @class foo
     def __init___(...):
         ...

instead of:

 @foo
 class bar:
     def __init___(...):
         ...

is a trivial difference in editing: you type "class " one more time.

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