Re: [Boost-users] [type_erasure] member function return any

Subject: Re: [Boost-users] [type_erasure] member function return any
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2017-03-06 15:45:44

AMDG

On 03/06/2017 04:59 AM, Mikhail Strelnikov via Boost-users wrote:
>
> I want to return type_erasure::any from a member function of a struct
> adapted by that same any. How can I do this?
> 

For this to work you need to forward declare
the Concept:

struct my_concept;
using my_any = boost::type_erasure::any<my_concept>;
struct my_concept : boost::mpl::vector<
  copy_constructible<>,
  assignable<>,
  callable<my_any(my_any)>> {};

> 
> #include <boost/type_erasure/any.hpp>
> #include <boost/type_erasure/callable.hpp>
> 
> using my_any = boost::type_erasure::any<
>     boost::mpl::vector<
>         boost::type_erasure::copy_constructible<>,
>         boost::type_erasure::assignable<>,
>         boost::type_erasure::callable<? ? ?>
>     >
>> ;
> 
> struct s
> {
>     my_any operator()(my_any v)
>     {
>         return v;
>     }
> };
> 
> int main()
> {
>     my_any t = s{};
>     t = t(t);
> }
> 

In Christ,
Steven Watanabe