Re: [Boost-users] Absolute Quanfusion : was Re: [fusion] transform a vector of values to refs

From: Joel de Guzman (joel_at_[hidden])
Date: 2006-09-09 14:33:46

Andy Little wrote:
> "Joel de Guzman" <joel_at_[hidden]> wrote
>> Andy Little wrote:
> 
>>> Maybe it would be a useful example in the fusion docs?. Anyway here it is
>>> FWIW:
>> Yes, definitely! I'll have to ask for documentation though. A simple
>> readme file is ok, plus, lots of comments.
> 
> OK. Bear in mind that its reliant 3 functors, multiply, add, and add-and-assign.
> In order to be agnostic regarding type deduction schemes ( my own, phoenix,
> lambda etc), my thought is to present particular versions of the functors
> implemented using Boost.Typeof.
> For the assignment one it needs to be implemented in terms of
> boost::reference_wrapper anyway and with the Lvalue as the right hand argument,
> which is AFAICS particular to the use of fold in fusion.
> 
> for example :
> 
> struct example_multiply{
> 
>         template <typename A , typename B>
>         struct result{
>                 typedef BOOST_TYPEOF_TPL(A() * B()) type;
>         };
> 
>         template <typename A, typename B>
>         typename result<A,B>::type
>         operator(A const & a, B const & b)
>         {
>             return  a * b;
>         }
> };
> 
> Boost.Typeof will after all be in the next release alongside Boost.Fusion
> Is that acceptable?

Sounds good. Okidoki.

Cheers,
-- 
Joel de Guzman
http://www.boost-consulting.com
http://spirit.sf.net