Steven D'Aprano wrote:
> I have some code that currently takes four different classes, A, B, C and
> D, and subclasses each of them in the same way:
>
> class MyA(A):
> def method(self, x):
> result = super(MyA, self).method(x)
> if result == "spam":
> return "spam spam spam"
> return result
> # many more methods overloaded
>
>
> class MyB(B):
> def method(self, x):
> result = super(MyB, self).method(x)
> if result == "spam":
> return "spam spam spam"
> return result
> # many more methods overloaded
>
>
> and so on, for MyC and MyD. There's a lot of duplicated code in there.
> What techniques do you suggest for reducing the code duplication? I
> thought about some variation of:
>
> names = "MyA MyB MyC MyD".split()
> bases = [A, B, C, D]
> d = dict-of-overloaded-methods
> for name, base in zip(names, bases):
> globals()[name] = type(name, [base], d)
>
>
> but I'm not sure that this is a good approach, or how to inject the right
> arguments to super in the dict.
>
> Any suggestions or guidelines?
You could use a mixin:
class Mixin(object):
def method(self, x):
result = super(Mixin, self).method(x)
if result == "spam":
return "spam spam spam"
return result
# ...
for name, base in zip(names, bases):
globals()[name] = type(name, (Mixin, base), {})
Peter
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