CTO wrote:
> Make doNothing a classmethod.
>
> class SomeClass:
>
> @classmethod
> def doNothing(cls):
> pass
>
> def function1(self):
> print "Running function 1"
>
> def function2(self, passedFunction=SomeClass.doNothing):
> print "Running passed function"
> passedFunction()
>
> someObject = SomeClass()
> someObject.function2()
> someObject.function2(someObject.function1)
To make that run without error you have to jump through a lot of hoops:
class SomeClass(object):
@classmethod
def doNothing(cls):
pass
def function1(self):
print "Running function 1"
def function2(self, passedFunction=SomeClass.doNothing):
print "Running passed function"
passedFunction()
SomeClass.function2 = function2
someObject = SomeClass()
someObject.function2()
someObject.function2(someObject.function1)
And if you don't need access to the instance you may not need access to the
class either. In this case you can simplify:
def doNothing():
pass
class SomeClass(object):
def function1(self):
print "Running function 1"
def function2(self, passedFunction=doNothing):
print "Running passed function"
passedFunction()
If you do need information about the state of the instance you can either
pass it explicitly
class SomeClass(object):
def doNothing(self):
pass
def function1(self):
print "Running function 1"
def function2(self, passedFunction=doNothing):
print "Running passed function"
passedFunction.__get__(self)()
or (better, I think) use a sentinel as shown by Bearophile.
Peter
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