Kirby Urner wrote:
As for decorators, at the moment I'm having no problems with the new syntax.Although everybody already knows this, I'm sure, a function actually is a class, so technically it is a function if you have all the things you get if you dir() a function. The only weird part here is that there's an endless number of functions (actually methods, which are treated exactly the same as functions for our purposes) inside these classes, like __repr__, so you can do:
You may have seen that post on the calculus. I was gratified to discover
that @ may be used to hand off the function that follows to a class (to some
__init__ method), so long as what's returned is likewise a function. Wait,
is that what I did? No, not exactly. I fed the function to class and
thereby get back an *object*, but this object was *callable*, and that's
enough to make its behavior *like* a function's. So everything worked.
Cool.
>>> def afunction(): return 0
>>> afunction()
0
>>> dir(afunction)
['__call__', '__class__', '__delattr__', '__dict__', '__doc__', '__get__', '__getattribute__', '__hash__', '__init__', '__module__', '__name__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__str__', 'func_closure', 'func_code', 'func_defaults', 'func_dict', 'func_doc', 'func_globals', 'func_name']
>>> dir(afunction.__repr__)
['__call__', '__class__', '__delattr__', '__doc__', '__getattribute__', '__hash__', '__init__', '__name__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__str__']
>>> dir(afunction.__repr__.__repr__)
['__call__', '__class__', '__delattr__', '__doc__', '__getattribute__', '__hash__', '__init__', '__name__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__str__']
>>> dir(afunction.__repr__.__repr__.__repr__)
['__call__', '__class__', '__delattr__', '__doc__', '__getattribute__', '__hash__', '__init__', '__name__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__str__']
>>> dir(afunction.__repr__.__repr__.__repr__.__repr__)
['__call__', '__class__', '__delattr__', '__doc__', '__getattribute__', '__hash__', '__init__', '__name__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__str__']
>>> afunction.__repr__.__repr__.__repr__.__repr__()
'<method-wrapper object at 0x41152c0c>'
I wonder how Python deals with this endless chain of __repr__'s. Maybe a function's attributes are generated on use, in which case they /aren't/ really an object at all, just a data type that looks like an object and acts like an object. I've never looked at any code having to do with Python in C or C++, so I wouldn't know.
One thing that would be very useful in the next version of Python (regarding decorators) would be the ability to use @return or maybe @print (although I can't think of a use for @print); the ability to put statements (I think that's what they are called) as decorators.
Tim
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