Re: [boost] [TypeErasure] Forward constructors and binded types

Subject: Re: [boost] [TypeErasure] Forward constructors and binded types
From: Larry Evans (cppljevans_at_[hidden])
Date: 2012-07-18 09:57:25

On 07/18/12 01:29, Vicente J. Botet Escriba wrote:
> Hi,,
> 
> In the example from the doc

http://steven_watanabe.users.sourceforge.net/type_erasure/libs/type_erasure/doc/html/boost_typeerasure/multi.html

> 
>     typedef mpl::vector<
>         copy_constructible<_a>,
>         copy_constructible<_b>,
>         copy_constructible<_c>,
>         constructible<_a(const _b&, const _c&)>
>     > construct;
> 
>     std::vector<double> vec;
>     int i = 10;
>     double d = 2.5;
>     tuple<construct, _a&, _b, _c> t(vec, i, d);
>     any<construct, _a> v(get<1>(t), get<2>(t));
> 
> I don't see which type is constructed and stored in v and how this type
> is given. That is I don't see how _a is binded. Could you help me?
> 

I'd guess that a std::vector<double>&, more specifically the
vec is stored as the _a& in the tuple<construct, _&a, _b, _c>.
Hmm...  Now I'm not sure anymore.  Maybe it's a new std::vector<double>
that's stored and the std::vector<double> CTOR args are
10 and double.  IOW the equivalent of:

  std::vector<double> v_a(10,2.5)

is stored in v?

Could the documentation on this be clarified a bit?

TIA.

-regards,
Larry