[C++-sig] CallPolicy for operators

[Jim Bosch]

On 01/27/2013 05:02 AM, Michael Wild wrote:
> Hi all
>
> Is there a way to apply a CallPolicy to operator definitions? In
> particular, I'm interested in the inplace operators (+=, -=, *=, /= and
> friends).
>
> To give a bit more context: The library I'm trying to wrap exposes some
> static const objects. So far, I have been able to wrap modifying
> function by having a registration facility for these static const
> objects and a custom CallPolicy that raises an AttributError when one
> tries to modify one of the registered objects.
>
> One option I see is to directly define __iadd__ etc. instead of using
> the built-in convenience operators. However, I'm not sure whether that
> has unintended side-effects. I haven't completely understood the
> operators implementation in bp, but it looks fairly involved.
>

I think directly implementing __iadd__ is probably your best bet.  I don't think there are any side-effects you need to worry about, but it would probably be a lot of boilerplate.  Do make sure you read up on how those methods are supposed to be implemented in pure-Python as regards to handling unexpected types, however, and make sure you follow the same rules in your C++ implementation.

Jim