staticmethod makes my brain hurt

[alex23]

On Nov 17, 12:30 pm, Roy Smith <r... at panix.com> wrote:
> class C:
>     @staticmethod
>     def foo():
>         pass
>
>     print "inside", foo, callable(foo)
>
> print "outside", C.foo, callable(C.foo)
>
> I don't understand.  Why is foo not callable inside of the class
> definition?

Consider this:

	>>> def foo(): pass
	...
	>>> foo = staticmethod(foo)
	>>> callable(foo)
	False

A staticmethod by itself does not appear to be callable.

Your internal 'foo' is referring to the staticmethod wrapper. Your
external 'C.foo' refers to the result returned by the class
mechanism's __getattr__, which I'm guessing is munged into a callable
at that point.

Where this comes up is that I'm trying to use a callable
> default in mongoengine:
>
> class User(Document):
>     @staticmethod
>     def _get_next_id():
>       [blah, blah, blah]
>       return id
>
>     user_id = IntField(required=True, default=_get_next_id)

What you're effectively trying to do is use a class before it has been
constructed to help construct itself.

Just define it as a helper function before the class declaration.