amcgregor · August 10, 2011 02:03 · pjenvey · Aug 10, 2011 · amcgregor · Aug 10, 2011
diff --git a/00-irc-log.textile b/00-irc-log.textile
diff --git a/02-solution.py b/02-solution.py
 def isclassmethod(cls, name):
    for cls in cls.mro():
        if name in cls.__dict__:
            if type(cls.__dict__[name]) is classmethod:
                return True
            
            return False
    
    return False

 def isstaticmethod(cls, name):
    for cls in cls.mro():
        if name in cls.__dict__:
            if type(cls.__dict__[name]) is staticmethod:
                return True
            
            return False
    
    return False


 class Foo(object):
    def foo(self):
        pass
    
    @classmethod
    def bar(cls):
        pass
    
    @staticmethod
    def baz():
        pass


 assert not isclassmethod(Foo, 'foo'), "Method is classmethod?"
 assert isclassmethod(Foo, 'bar'), "Classmethod isn't?"
 assert isstaticmethod(Foo, 'baz'), "Staticmethod isn't?"
GothAlice	How do I determine if a given object is a @classmethod, and, additionally, how do I determine if it is a @staticmethod? ¹
KirkMcDonald	GothAlice: Why would you care?
GothAlice	KirkMcDonald: Enforcing interfaces, not that it matters.
dash	GothAlice: you’re right, it doesn’t matter
_habnabit	GothAlice, if you wanted an answer to the question as asked, why don’t you try ##python-friendly? #python is about writing better code.
nedbat	GothAlice: what KirkMcDonald should have said was, “The Python culture is to not check ahead of time, do you have an unusual requirement that means you really have to know?”
GothAlice	_habnabit: Cute, thank you for living up to expectations.
nedbat	_habnabit: you don’t have to treat people that way.
GothAlice	nedbat: Assume yes, I do have a requirement that needs this.
message144	heh today i learned that ##python-friendly is a real thing
GothAlice	nedbat: No worries, I expect that kind of behaviour from him and a few select others.
nedbat	GothAlice: the inspect module has lots of tools, not sure if it covers what you’re looking for.
GothAlice	nedbat: I’ve already looked, it doesn’t.
GothAlice	Also, _habnabit, it’s against channel rules to advertise other channels; or it was, last time I checked.
KirkMcDonald	GothAlice: The answer is obvious if you know how classmethod and staticmethod work. ²
nedbat	KirkMcDonald: that’s not that helpful an answer either.
GothAlice	KirkMcDonald: Again, thank you for meeting expectations. Is it any wonder I created ##python-friendly?
KirkMcDonald	GothAlice: Just yank the objects out of the thing and see what they are. ²
GothAlice	KirkMcDonald: Still not helpful. You do realize you’re wasting not just my time, but yours as well?
dash	GothAlice: You already know what to expect when you come here.
nedbat	dash: why is it ok for her to expect curt rude unhelpful answers?
dash	GothAlice: So please don’t expect us to be moved by your complaints about it.
Yhg1s	nedbat: there’s quite a bit of history involved.
dash	nedbat: A long history of disagreement.
nedbat	Yhg1s: I’m getting that sense, but in my experience, GothAlice is not unusual in this regard. Lots of people have come to expect those answers.
KirkMcDonald	nedbat: We’re not here to just answer asked questions.
Yhg1s	nedbat: if the questions are about bad ideas, then yes, many people won’t give direct answers. With good reason. All too often, if they are given something that does what they seem to want, it’ll just ruin their design and they’ll come back crying later.
Yhg1s	nedbat: #python is about helping people write Python, not get something working.
nedbat	i’ve heard all this before. Some people disagree. I won’t take more of your time.
GothAlice	I think that’s the primary conflict, here. I feel no need to justify myself when asking a question about a real problem I’m encountering. I’ve been programming commercially since I was 9, and generally my OSS code speaks for itself. I’m not an idiot, don’t treat me as one.
Yhg1s	nedbat: this is why there’s other channels :)
Yhg1s	GothAlice: And yet you insist on treating us as idiots. Thanks. ³
GothAlice	However, my particular use case involves writing an interface declaration and enforcement system, similar to zope.interface, but a fair bit simpler.
KirkMcDonald	GothAlice: If you find that you actually need to do this sort of metaprogramming nonsense, I am surprised you don’t know how to do it. ⁴
nedbat	KirkMcDonald: we’ve established that you are surprised. Now, do you know the answer?
KirkMcDonald	That you have sufficient skill for this kind of metaprogramming to be a need but insufficient skill to just do it is strange to me. ⁴
dash	GothAlice: I would note that not even zope.interface checks if things are staticmethods or classmethods. :)
KirkMcDonald	I gave the answer: Get the objects. See what they are instances of. ²
dash	GothAlice: So your approach already sounds less simple
GothAlice	sighs.
nedbat	KirkMcDonald: when i get a classmethod from an object, its type is “instancemethod”.
NelleV	GothAlice: maybe you’ll have more answers on the python-list mailing list
Yhg1s	nedbat: you have to get it from the class, of course.
KirkMcDonald	To get the actual classmethod object, you don’t even get it from the class. You need to sidestep the descriptor protocol.
Yhg1s	some knowledge of how these things work is necessary, if you want to do these kinds of things. There’s several decent documents on the interwebs that explain how classes, metaclasses and descriptors like staticmethod and classmethod work. [17:29:43]
GothAlice	Yhg1s: A ha, descriptor protocol. Thank you for finally being useful. type(obj).mro() + dict here I come. ⁵
Yhg1s	GothAlice: ‘finally being useful’. Thanks again.
Yhg1s	GothAlice: your hostile attitude is as old as your passive-agressiveness. Please go away, learn to act like a civil person or ask better questions (preferably all three.) ⁶
GothAlice	Yhg1s: Just giving credit where credit is due. Those two words took 15 minutes and solved my problem. Additionally, the question was perfectly sound. Your insistence on correcting the purpose of others’ code is the problem.
Kaedenn	GothAlice: Welcome to #python
Kaedenn	GothAlice: I see you’re new here
17:33:40	mode (+o Yhg1s) by ChanServ
17:33:51	mode (+b ![email protected].*) by Yhg1s
17:33:52	You have been kicked by Yhg1s: (Don’t come back.)
	def isclassmethod(cls, name):
	for cls in cls.mro():
	if name in cls.__dict__:
	if type(cls.__dict__[name]) is classmethod:
	return True

	return False

	return False

	def isstaticmethod(cls, name):
	for cls in cls.mro():
	if name in cls.__dict__:
	if type(cls.__dict__[name]) is staticmethod:
	return True

	return False

	return False


	class Foo(object):
	def foo(self):
	pass

	@classmethod
	def bar(cls):
	pass

	@staticmethod
	def baz():
	pass


	assert not isclassmethod(Foo, 'foo'), "Method is classmethod?"
	assert isclassmethod(Foo, 'bar'), "Classmethod isn't?"
	assert isstaticmethod(Foo, 'baz'), "Staticmethod isn't?"