C++ overloaded operators and D

[via Digitalmars-d]

On Wednesday, 12 November 2014 at 19:32:32 UTC, IgorStepanov 
wrote:
> On Wednesday, 12 November 2014 at 14:41:17 UTC, Marc Schütz 
> wrote:
>> On Wednesday, 12 November 2014 at 11:43:36 UTC, IgorStepanov 
>> wrote:
>>> C++ and D provides different behaviour for operator 
>>> overloading.
>>> D has a opIndex + opIndexAssign overloads, and if we want to 
>>> map opIndex to operator[], we must to do something with 
>>> opIndexAssign.
>>
>> operator[] can be mapped to opIndex just fine, right? Only 
>> opIndexAssign wouldn't be accessible from C++ via an operator, 
>> but that's because the feature doesn't exist. We can still 
>> call it via its name opIndexAssign.
>>
>>> operator< and operator> can't be mapped to D. Same for 
>>> operator&.
>>
>> That's true. Maybe we can just live with pragma(mangle) for 
>> them, but use D's op... for all others?
>>
>>> Binary arithmetic operators can't be mapped to D, if them 
>>> implemented as static functions:
>>>
>>> Foo operator+(int a, Foo f); //unable to map it to D, because 
>>> static module-level Foo opAdd(int, Foo) will not provide the 
>>> same behaviour as operator+ in D.
>>> Thus: C++ and D overloaded operators should live in different 
>>> worlds.
>>
>> Can't we map both static and member operators to opBinary 
>> resp. opBinaryRight members in this case? How likely is it 
>> that both are defined on the C++ side, and if they are, how 
>> likely is it that they will behave differently?
>
> opBinary(Right) is a template-functions. You can't add previous 
> declaration for it to struct:
>
> //C++
> struct Foo
> {
>     Foo operator+(const Foo&);
> };
>
> Foo operator+(int, const Foo&);
>
> //D
> extern(C++)
> struct struct Foo
> {
>     Foo opBinary!"+"(const ref Foo); //???

I see...

> }
>
> Foo opBinary!"+"(int, const ref Foo); //???

But this would of course be opBinaryRight, and inside struct Foo.