Re: [Boost-users] [units,typeof] meta_multiply units?

Subject: Re: [Boost-users] [units,typeof] meta_multiply units?
From: Rupert Mazzucco (mazzucco_at_[hidden])
Date: 2009-09-11 10:11:11

> say I have a functor F which takes an argument of type
> 
> F::arg_type = quantity<time>
> 
> and returns a value of type
> 
> F::ret_type = quantity<velocity>
> 
> Now I want to write an integration function, which should
> return the correct type, something like
> 
>   template<class F>
>   F::ret_type*F::arg_type    // only conceptually
>   integrate(F& f, typename F::arg_type a, typename F::arg_type b);
> 
> so instantiating this with the above functor should produce a
> return type quantity<time*velocity==length>. How can I combine
> F::arg_type and F::ret_type to produce the correct return type
> for the function template?

Attempted to solve this with the help of boost.typeof:

  template<class F>
  BOOST_TYPEOF_TPL(F::ret_type() * F::arg_type())
  integrate(F& f, typename F::arg_type a, typename F::arg_type b);

but MVC9 produces a

   error C2064: term does not evaluate to a function taking 0 arguments

for the default constructor calls in the macro argument. Any ideas welcome.

Thanks
-- 
Rupert Mazzucco         <mazzucco_at_[hidden]>
Research Scholar, Evolution and Ecology Program
IIASA - Institute for Applied Systems Analysis
Schlossplatz 1, 2361 Laxenburg, Austria
Phone: [phone]   Fax: [phone]