What are the elegant ways to do MixIns in Python?
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by Slava Vishnyakov
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Published on 2010-05-03T10:23:21Z
Indexed on
2010/05/03
10:28 UTC
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I need to find an elegant way to do 2 kinds of MixIns.
First:
class A(object):
def method1(self):
do_something()
Now, a MixInClass
should make method1
do this: do_other()
-> A.method1()
-> do_smth_else()
- i.e. basically "wrap" the older function. I'm pretty sure there must exist a good solution to this.
Second:
class B(object):
def method1(self):
do_something()
do_more()
In this case, I want MixInClass2
to be able to inject itself between do_something()
and do_more()
, i.e.: do_something()
-> MixIn.method1
-> do_more()
. I understand that probably this would require modifying class B
- that's ok, just looking for simplest ways to achieve this.
These are pretty trivial problems and I actually solved them, but my solution is tainted.
Fisrt one by using self._old_method1 = self.method1(); self.method1() = self._new_method1();
and writing _new_method1()
that calls to _old_method1()
.
Problem: multiple MixIns will all rename to _old_method1 and it is inelegant.
Second MixIn one was solved by creating a dummy method call_mixin(self): pass
and injecting it between calls and defining self.call_mixin()
. Again inelegant and will break on multiple MixIns..
Any ideas?
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