On Apr 14, 4:09 am, Steven D'Aprano
<ste...@remove.this.cybersource.com.au> wrote:
> I have a subclass of int where I want all the standard arithmetic
> operators to return my subclass, but with no other differences:
>
> class MyInt(int):
> def __add__(self, other):
> return self.__class__(super(MyInt, self).__add__(other))
> # and so on for __mul__, __sub__, etc.
>
> My quick-and-dirty count of the __magic__ methods that need to be over-
> ridden comes to about 30. That's a fair chunk of unexciting boilerplate.
>
Something like this maybe?
def takesOneArg(fn):
try:
fn(1)
except TypeError:
return False
else:
return True
class MyInt(int): pass
template = "MyInt.__%s__ = lambda self, other: self.__class__(super
(MyInt, self).__%s__(other))"
fns = [fn for fn in dir(int) if fn.startswith('__') and takesOneArg
(getattr(1,fn))]
print fns
for fn in fns:
exec(template % (fn,fn))
Little harm in this usage of exec, since it is your own code that you
are running.
-- Paul
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