Re: syntax suggestion

David Abrahams wrote:

> Alexander Nasonov <[email protected]> writes:
> 
>> Daniel Wallin wrote:
>>
>>> Alexander Nasonov wrote:
>>>> I'd like to see inheritance more natural in langbinding. What do you
>>>> think if inheritance relationships could be exposed like this:
>>>> 
>>>> class_<C>("C")
>>>>     , public_<A>
>>>>     , public_<B>
>>>> [
>>>>     // ...
>>>> ];
>>> 
>>> The [] syntax still won't work (IMO) for declaring classes. So you'd end
>>> up with something like:
> 
> Not to mention that the []s will bind more closely to public_<B> than
> to the class_ object. 
Oops

> If we end up building an AST for the
> class declaration and then walking over it to evaluate it, I fear
> we're going to end up overstressing many compilers.
> 
>>>      class_<C>("C")
>>>          .public_<A>()
>>>          .public_<B>()
>>>        .def(..)
>>>        .def(..)
>>>        ;
>>
>> I think it's possible to implement []-style but I'm not sure how much
>> time it would take to compile.
> 
> Agreed, it's possible. The compilation time is IMO a serious concern.

I agree, it's really serious.

>>> Although it looks kind of cool, 'public_' is completely redundant since
>>> we are only interested in accessible bases anyway.
>>
>> Not sure about this. We may need access to protected C++ bases from
>> non-C++ class (I don't know how to implement it elegantly, though).
> 
> Actually I think the issue here is that we don't need to represent
> access.  Why would the system care whether a base was private or
> protected or public?

The system could make a decision if its overload resolution algorithm ended
up with a base member function. Members of protected base can be accessed
only from member functions of derived class.

-- 
Alexander Nasonov
Independent Developer and Consultant




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