Re: [boost] boost::mem_fn suggestion/question

From: Marcus Lindblom (macke_at_[hidden])
Date: 2007-05-15 12:24:11

Peter Dimov wrote:
> Marcus Lindblom wrote:
>
>   
>> In the bind()-cases, it uses mem_fn to call the actual function:
>>
>> template<class C>
>> template<class T, typename A1, typename A2>
>> void  ScriptClassImpl<C>::ElemBinder::bind(void (T::*f)(A1, A2),
>>                                          const char* n1, const char* n2) {
>>    BOOST_STATIC_ASSERT((::boost::is_base_and_derived<T,
>>    C>::value||::boost::is_same<T, C>::value));
>>
>>    typedef boost::function<void (T&, A1, A2)> func_type;
>>    *m_f = xml::mkApplyElemFunctor<func_type>(boost::mem_fn(f),
>> *m_log).arg(n1).arg(n2);
>> }
>>     
>
> Sounds sensible, although you can use something like
>
> *m_f = boost::bind( f, _1,
>
>     boost::bind( getArg<A1>, _2, n1 ),
>     boost::bind( getArg<A2>, _2, n2 ) );
>
> here.
>   
Hmm. Yup, that might be possible. I'll have to think about it. :)
> I'm somewhat reluctant to introduce features into boost::mem_fn since 
> std::tr1::mem_fn and the upcoming std::mem_fn don't/won't have them. If you 
> start using ::argN_type, you won't be able to switch to std::mem_fn once it 
> becomes available. Of course if this is not a concern for the Boost 
> community we can easily add the typedefs and the arity. 
>   
Valid point. Perhaps function_traits could be extended to handle all 
type of function objects as well as regular functions, somehow?

Cheers,
/Marcus