On 02/24/2015 05:56 PM, Gregory P. Smith wrote:

inspect.getargspec(method) and inspect.signature(method) both include the 'self' parameter but how are we to figure out from method itself that it is actually bound and that its first parameter is expected to be a bound instance?

Given the mechanisms involved, surely this question is a bit nonsensical? The function doesn't "expect" anything, it's just a function. (I remind you, Python 3 dropped the whole concept of an "unbound method".) If it happens to live inside a class, and it's accessed through an instance of the class, then the first parameter gets bound.

Consider:

>>> class A:
... def x(self, a): print(a)
...
>>> a = A()

inspect.signature(A.x).parameters has two parameters, "self" and "a".
inspect.signature(a.x).parameters has only one parameter, "a".

I claiim this is what you want. It's analagous to a functools.partial object. It would be awfully confusing if the signature of a functools.partial object include the parameters handled by the partial object.

IMO inspect.getargspec and inspect.getfullargspec get this wrong; for a.x they include the "self" parameter. If you were constructing a call to this function dynamically you'd include one too many parameters.

/arry