[C++-sig] virtual functions with default implementation

[Stefan Seefeld]

Hi Alex,

On 17/08/15 02:54 PM, Alex Mohr wrote:
> On 8/17/2015 11:39 AM, Stefan Seefeld wrote:
>> For the case with default implementation, the tutorial gives this
>> wrapper:
>>
>>    struct BaseWrap : Base, bpl::wrapper<Base>
>>    {
>>      virtual std::string func() const
>>      {
>>        if (bpl::override f = this->get_override("func"))
>>          return f();
>>        else
>>          return Base::func();
>>      }
>>      std::string default_func() const { return this->Base::func();}
>>    };
>>
>> and it seems to me much more natural to implement the "default" case
>> directly in the "else" branch above, rather than add it to the
>> "def()" call.
>
> I think this might be so that python can invoke the superclass (C++)
> implementation directly in its override, but I'm not 100% sure.

Ah, that's it !

I just tried

Konsole output
>>> class C(Base):
...     def func(self): return super(C, self).func()

which yields an infinite recursion (until stack overflow) unless I
define "func" with the additional default function.

Thanks !

        Stefan


-- 

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