Re: [Boost-users] [MPL][FUSION] generate fusion::map from mpl::vector

Manuel Jung writes:

Well this is what i've got so far:

template< typename OutSignatures > class filter_impl{ typedef typename mpl::transform< OutSignatures, boost::promise_streammpl::_1 >::type OutStreams;

typedef typename mpl::transform< OutSignatures, OutStreams, fusion::make_pair< mpl::_1, mpl::_2 > >::type OutPairs;

typedef typename fusion::result_of::as_map< fusion::vector< OutPairs >

...

::type Out_type;

}

This compiles fine. But i'm not able to generate some fusion::map from the Out_type. I get compiling errors than.

Upon looking at your original code further, there does indeed appear to be a trivial fix to get it to compile -- add result_of:: before make_pair, and get rid of fusion::vector<> around OutPairs: template<typename OutSignatures> struct filter_impl { typedef typename mpl::transform < OutSignatures, boost::promise_streammpl::_1 >::type OutStreams; typedef typename mpl::transform < OutSignatures, OutStreams, fusion::result_of::make_pair >::type OutPairs; typedef typename fusion::result_of::as_map<OutPairs>::type OutMap; }; This can now be reduced to the more succinct: template<typename OutSignatures> struct filter_impl { typedef typename fusion::result_of::as_map < typename mpl::transform < OutSignatures, fusion::result_of::make_pair < mpl::_1, boost::promise_streammpl::_1 > >::type >::type OutMap; };