Re: [boost] [Proposal] A little reasonable modification of boost::bind_t

Subject: Re: [boost] [Proposal] A little reasonable modification of boost::bind_t
From: Antony Polukhin (antoshkka_at_[hidden])
Date: 2013-05-11 09:18:35

2013/5/11 Arthur Athrun <athrunarthur_at_[hidden]>:
> Hi, everyone,
>
> I'd like to propose a little modification of boost:: bind to expose more
> information in boost:: _bi:: bind_t.
<...>
> With such modifications, we can access all binded arguments in the
> boost::_bi::bind_t. Here is a showcase.
>
> template<class T, class VT>void Test(VT t, T * p = 0)
> {
>         //This parameter is not binded, so ignore it!
> }template<class T, class VT>void Test(VT t, typename T::val_type * p = 0)
> {
>         //T::val_type is the parameter's type，
>         //and can use boost::is_same<T::val_type, ID_t>::value to check it!
>         std::cout<<"great! we get a value here!"<<t.get()<<std::endl;
> }
>
> template <class R, class F, class A1, class A2>void
> retrive_args(boost::_bi::bind_t<R, F, boost::_bi::list2<A1, A2> > &
> f)
> {
>         Test<A1>(f.arguments()[_1]);
>         Test<A2>(f.arguments()[_2]);
> }
>
> int f(int a, double b)
> {
>         std::cout<<a<<std::endl;
>         return a;
> }
>
> int main(int argc, char * argv[])
> {
>         double t = 1.0;
>         retrive_args(boost::bind(f, _1, 0.2)); //Here will retrive the second
> parameters only.
>         return 0;
> }
>
> I don't know if I get the right way to implement it. Please let me
> know if you have another implementation. Any comments or ideas will be
> appreciated. Thanks.

Simpler solution would be to use boost::tuple or boost::fusion::vector
to store and pass parameters separetly from function. Only after all
the work with parameters done, call boost::bind and retrieve your
functional object.

--
Best regards,
Antony Polukhin