Re: [Boost-users] [mpl] at_c type compiler error

From: Chris Weed (chrisweed_at_[hidden])
Date: 2007-10-18 10:24:28

On 10/18/07, Vinzenz 'evilissimo' Feenstra <evilissimo_at_[hidden]> wrote:
> Vinzenz 'evilissimo' Feenstra schrieb:
> > Chris Weed schrieb:
> >> Hi,
> >> I can't figure out why the following code generates a compile error
> >> with gcc 3.4:
> > Hi,
> >
> > shouldn't it be:
> >
> >   template<typename E,typename T>
> >   typename boost::tuples::element<typename
> > boost::mpl::at_c<E,0>::type::value,T>::type
> >   foo(E e,T t)
> >   {
> >     return t.get<0>();
> >   }
> >
> > Regards,
> > Vinzenz
> Nevermind this wasn't the problem. Here's a working one ;)
>
> #include <boost/mpl/vector_c.hpp>
> #include <boost/mpl/at.hpp>
> #include <boost/tuple/tuple.hpp>
>
> template<typename E,typename T>
> typename boost::tuples::element<
>           boost::mpl::at_c<E,0>::type::value , T
>           >::type
> foo(E e, T t)
> {
>    return boost::get<0>(t);
> }
>
> int main()
> {
>    typedef boost::mpl::vector_c<int,0,1> elements;
>    boost::tuple<int> t(1);
>    foo(elements(),t);
> }

That fixes it, but I don't see why, or what this change had to do with
the error message.
Thanks,
Chris