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

From: Peter Dimov (pdimov_at_[hidden])
Date: 2007-05-15 12:18:42

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.

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.