Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: // depends_on.hpp
Chris@16: //
Chris@16: //  Copyright 2005 Eric Niebler. Distributed under the Boost
Chris@16: //  Software License, Version 1.0. (See accompanying file
Chris@16: //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #ifndef BOOST_ACCUMULATORS_FRAMEWORK_DEPENDS_ON_HPP_EAN_28_10_2005
Chris@16: #define BOOST_ACCUMULATORS_FRAMEWORK_DEPENDS_ON_HPP_EAN_28_10_2005
Chris@16: 
Chris@16: #include <boost/version.hpp>
Chris@16: #include <boost/mpl/end.hpp>
Chris@16: #include <boost/mpl/map.hpp>
Chris@16: #include <boost/mpl/set.hpp>
Chris@16: #include <boost/mpl/copy.hpp>
Chris@16: #include <boost/mpl/fold.hpp>
Chris@16: #include <boost/mpl/size.hpp>
Chris@16: #include <boost/mpl/sort.hpp>
Chris@16: #include <boost/mpl/insert.hpp>
Chris@16: #include <boost/mpl/assert.hpp>
Chris@16: #include <boost/mpl/remove.hpp>
Chris@16: #include <boost/mpl/vector.hpp>
Chris@16: #include <boost/mpl/inherit.hpp>
Chris@16: #include <boost/mpl/identity.hpp>
Chris@16: #include <boost/mpl/equal_to.hpp>
Chris@16: #include <boost/mpl/contains.hpp>
Chris@16: #include <boost/mpl/transform.hpp>
Chris@16: #include <boost/mpl/is_sequence.hpp>
Chris@16: #include <boost/mpl/placeholders.hpp>
Chris@16: #include <boost/mpl/insert_range.hpp>
Chris@16: #include <boost/mpl/back_inserter.hpp>
Chris@16: #include <boost/mpl/transform_view.hpp>
Chris@16: #include <boost/mpl/inherit_linearly.hpp>
Chris@16: #include <boost/type_traits/is_base_and_derived.hpp>
Chris@16: #include <boost/preprocessor/repetition/repeat.hpp>
Chris@16: #include <boost/preprocessor/repetition/enum_params.hpp>
Chris@16: #include <boost/preprocessor/facilities/intercept.hpp>
Chris@16: #include <boost/accumulators/accumulators_fwd.hpp>
Chris@16: #include <boost/fusion/include/next.hpp>
Chris@16: #include <boost/fusion/include/equal_to.hpp>
Chris@16: #include <boost/fusion/include/value_of.hpp>
Chris@16: #include <boost/fusion/include/mpl.hpp>
Chris@16: #include <boost/fusion/include/end.hpp>
Chris@16: #include <boost/fusion/include/begin.hpp>
Chris@16: #include <boost/fusion/include/cons.hpp>
Chris@16: 
Chris@16: namespace boost { namespace accumulators
Chris@16: {
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     // as_feature
Chris@16:     template<typename Feature>
Chris@16:     struct as_feature
Chris@16:     {
Chris@16:         typedef Feature type;
Chris@16:     };
Chris@16: 
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     // weighted_feature
Chris@16:     template<typename Feature>
Chris@16:     struct as_weighted_feature
Chris@16:     {
Chris@16:         typedef Feature type;
Chris@16:     };
Chris@16: 
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     // feature_of
Chris@16:     template<typename Feature>
Chris@16:     struct feature_of
Chris@16:     {
Chris@16:         typedef Feature type;
Chris@16:     };
Chris@16: 
Chris@16:     namespace detail
Chris@16:     {
Chris@16:         ///////////////////////////////////////////////////////////////////////////
Chris@16:         // feature_tag
Chris@16:         template<typename Accumulator>
Chris@16:         struct feature_tag
Chris@16:         {
Chris@16:             typedef typename Accumulator::feature_tag type;
Chris@16:         };
Chris@16: 
Chris@16:         template<typename Feature>
Chris@16:         struct undroppable
Chris@16:         {
Chris@16:             typedef Feature type;
Chris@16:         };
Chris@16: 
Chris@16:         template<typename Feature>
Chris@16:         struct undroppable<tag::droppable<Feature> >
Chris@16:         {
Chris@16:             typedef Feature type;
Chris@16:         };
Chris@16: 
Chris@16:         // For the purpose of determining whether one feature depends on another,
Chris@16:         // disregard whether the feature is droppable or not.
Chris@16:         template<typename A, typename B>
Chris@16:         struct is_dependent_on
Chris@16:           : is_base_and_derived<
Chris@16:                 typename feature_of<typename undroppable<B>::type>::type
Chris@16:               , typename undroppable<A>::type
Chris@16:             >
Chris@16:         {};
Chris@16: 
Chris@16:         template<typename Feature>
Chris@16:         struct dependencies_of
Chris@16:         {
Chris@16:             typedef typename Feature::dependencies type;
Chris@16:         };
Chris@16: 
Chris@16:         // Should use mpl::insert_range, but doesn't seem to work with mpl sets
Chris@16:         template<typename Set, typename Range>
Chris@16:         struct set_insert_range
Chris@16:           : mpl::fold<
Chris@16:                 Range
Chris@16:               , Set
Chris@16:               , mpl::insert<mpl::_1, mpl::_2>
Chris@16:             >
Chris@16:         {};
Chris@16: 
Chris@16:         template<typename Features>
Chris@16:         struct collect_abstract_features
Chris@16:           : mpl::fold<
Chris@16:                 Features
Chris@16:               , mpl::set0<>
Chris@16:               , set_insert_range<
Chris@16:                     mpl::insert<mpl::_1, feature_of<mpl::_2> >
Chris@16:                   , collect_abstract_features<dependencies_of<mpl::_2> >
Chris@16:                 >
Chris@16:             >
Chris@16:         {};
Chris@16: 
Chris@16:         template<typename Features>
Chris@16:         struct depends_on_base
Chris@16:           : mpl::inherit_linearly<
Chris@16:                 typename mpl::sort<
Chris@16:                     typename mpl::copy<
Chris@16:                         typename collect_abstract_features<Features>::type
Chris@16:                       , mpl::back_inserter<mpl::vector0<> >
Chris@16:                     >::type
Chris@16:                   , is_dependent_on<mpl::_1, mpl::_2>
Chris@16:                 >::type
Chris@16:                 // Don't inherit multiply from a feature
Chris@16:               , mpl::if_<
Chris@16:                     is_dependent_on<mpl::_1, mpl::_2>
Chris@16:                   , mpl::_1
Chris@16:                   , mpl::inherit<mpl::_1, mpl::_2>
Chris@16:                 >
Chris@16:             >::type
Chris@16:         {
Chris@16:         };
Chris@16:     }
Chris@16: 
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     /// depends_on
Chris@16:     template<BOOST_PP_ENUM_PARAMS(BOOST_ACCUMULATORS_MAX_FEATURES, typename Feature)>
Chris@16:     struct depends_on
Chris@16:       : detail::depends_on_base<
Chris@16:             typename mpl::transform<
Chris@16:                 mpl::vector<BOOST_PP_ENUM_PARAMS(BOOST_ACCUMULATORS_MAX_FEATURES, Feature)>
Chris@16:               , as_feature<mpl::_1>
Chris@16:             >::type
Chris@16:         >
Chris@16:     {
Chris@16:         typedef mpl::false_ is_weight_accumulator;
Chris@16:         typedef
Chris@16:             typename mpl::transform<
Chris@16:                 mpl::vector<BOOST_PP_ENUM_PARAMS(BOOST_ACCUMULATORS_MAX_FEATURES, Feature)>
Chris@16:               , as_feature<mpl::_1>
Chris@16:             >::type
Chris@16:         dependencies;
Chris@16:     };
Chris@16: 
Chris@16:     namespace detail
Chris@16:     {
Chris@16:         template<typename Feature>
Chris@16:         struct matches_feature
Chris@16:         {
Chris@16:             template<typename Accumulator>
Chris@16:             struct apply
Chris@16:               : is_same<
Chris@16:                     typename feature_of<typename as_feature<Feature>::type>::type
Chris@16:                   , typename feature_of<typename as_feature<typename feature_tag<Accumulator>::type>::type>::type
Chris@16:                 >
Chris@16:             {};
Chris@16:         };
Chris@16: 
Chris@16:         template<typename Features, typename Accumulator>
Chris@16:         struct contains_feature_of
Chris@16:         {
Chris@16:             typedef
Chris@16:                 mpl::transform_view<Features, feature_of<as_feature<mpl::_> > >
Chris@16:             features_list;
Chris@16: 
Chris@16:             typedef
Chris@16:                 typename feature_of<typename feature_tag<Accumulator>::type>::type
Chris@16:             the_feature;
Chris@16: 
Chris@16:             typedef
Chris@16:                 typename mpl::contains<features_list, the_feature>::type
Chris@16:             type;
Chris@16:         };
Chris@16: 
Chris@16:         // This is to work around a bug in early versions of Fusion which caused
Chris@16:         // a compile error if contains_feature_of<List, mpl::_> is used as a
Chris@16:         // predicate to fusion::find_if
Chris@16:         template<typename Features>
Chris@16:         struct contains_feature_of_
Chris@16:         {
Chris@16:             template<typename Accumulator>
Chris@16:             struct apply
Chris@16:               : contains_feature_of<Features, Accumulator>
Chris@16:             {};
Chris@16:         };
Chris@16: 
Chris@16:         template<
Chris@16:             typename First
Chris@16:           , typename Last
Chris@16:           , bool is_empty = fusion::result_of::equal_to<First, Last>::value
Chris@16:         >
Chris@16:         struct build_acc_list;
Chris@16: 
Chris@16:         template<typename First, typename Last>
Chris@16:         struct build_acc_list<First, Last, true>
Chris@16:         {
Chris@101:             typedef fusion::nil_ type;
Chris@16: 
Chris@16:             template<typename Args>
Chris@101:             static fusion::nil_
Chris@16:             call(Args const &, First const&, Last const&)
Chris@16:             {
Chris@101:                 return fusion::nil_();
Chris@16:             }
Chris@16:         };
Chris@16: 
Chris@16:         template<typename First, typename Last>
Chris@16:         struct build_acc_list<First, Last, false>
Chris@16:         {
Chris@16:             typedef
Chris@16:                 build_acc_list<typename fusion::result_of::next<First>::type, Last>
Chris@16:             next_build_acc_list;
Chris@16: 
Chris@16:             typedef fusion::cons<
Chris@16:                 typename fusion::result_of::value_of<First>::type
Chris@16:               , typename next_build_acc_list::type>
Chris@16:             type;
Chris@16: 
Chris@16:             template<typename Args>
Chris@16:             static type
Chris@16:             call(Args const &args, First const& f, Last const& l)
Chris@16:             {
Chris@16:                 return type(args, next_build_acc_list::call(args, fusion::next(f), l));
Chris@16:             }
Chris@16:         };
Chris@16: 
Chris@16:         namespace meta
Chris@16:         {
Chris@16:             template<typename Sequence>
Chris@16:             struct make_acc_list
Chris@16:               : build_acc_list<
Chris@16:                     typename fusion::result_of::begin<Sequence>::type
Chris@16:                   , typename fusion::result_of::end<Sequence>::type
Chris@16:                 >
Chris@16:             {};
Chris@16:         }
Chris@16: 
Chris@16:         template<typename Sequence, typename Args>
Chris@16:         typename meta::make_acc_list<Sequence>::type
Chris@16:         make_acc_list(Sequence const &seq, Args const &args)
Chris@16:         {
Chris@16:             return meta::make_acc_list<Sequence>::call(args, fusion::begin(seq), fusion::end(seq));
Chris@16:         }
Chris@16: 
Chris@16:         ///////////////////////////////////////////////////////////////////////////
Chris@16:         // checked_as_weighted_feature
Chris@16:         template<typename Feature>
Chris@16:         struct checked_as_weighted_feature
Chris@16:         {
Chris@16:             typedef typename as_feature<Feature>::type feature_type;
Chris@16:             typedef typename as_weighted_feature<feature_type>::type type;
Chris@16:             // weighted and non-weighted flavors should provide the same feature.
Chris@16:             BOOST_MPL_ASSERT((
Chris@16:                 is_same<
Chris@16:                     typename feature_of<feature_type>::type
Chris@16:                   , typename feature_of<type>::type
Chris@16:                 >
Chris@16:             ));
Chris@16:         };
Chris@16: 
Chris@16:         ///////////////////////////////////////////////////////////////////////////
Chris@16:         // as_feature_list
Chris@16:         template<typename Features, typename Weight>
Chris@16:         struct as_feature_list
Chris@16:           : mpl::transform_view<Features, checked_as_weighted_feature<mpl::_1> >
Chris@16:         {
Chris@16:         };
Chris@16: 
Chris@16:         template<typename Features>
Chris@16:         struct as_feature_list<Features, void>
Chris@16:           : mpl::transform_view<Features, as_feature<mpl::_1> >
Chris@16:         {
Chris@16:         };
Chris@16: 
Chris@16:         ///////////////////////////////////////////////////////////////////////////
Chris@16:         // accumulator_wrapper
Chris@16:         template<typename Accumulator, typename Feature>
Chris@16:         struct accumulator_wrapper
Chris@16:           : Accumulator
Chris@16:         {
Chris@16:             typedef Feature feature_tag;
Chris@16: 
Chris@16:             accumulator_wrapper(accumulator_wrapper const &that)
Chris@16:               : Accumulator(*static_cast<Accumulator const *>(&that))
Chris@16:             {
Chris@16:             }
Chris@16: 
Chris@16:             template<typename Args>
Chris@16:             accumulator_wrapper(Args const &args)
Chris@16:               : Accumulator(args)
Chris@16:             {
Chris@16:             }
Chris@16:         };
Chris@16: 
Chris@16:         ///////////////////////////////////////////////////////////////////////////
Chris@16:         // to_accumulator
Chris@16:         template<typename Feature, typename Sample, typename Weight>
Chris@16:         struct to_accumulator
Chris@16:         {
Chris@16:             typedef
Chris@16:                 accumulator_wrapper<
Chris@16:                     typename mpl::apply2<typename Feature::impl, Sample, Weight>::type
Chris@16:                   , Feature
Chris@16:                 >
Chris@16:             type;
Chris@16:         };
Chris@16: 
Chris@16:         template<typename Feature, typename Sample, typename Weight, typename Tag, typename AccumulatorSet>
Chris@16:         struct to_accumulator<Feature, Sample, tag::external<Weight, Tag, AccumulatorSet> >
Chris@16:         {
Chris@16:             BOOST_MPL_ASSERT((is_same<Tag, void>));
Chris@16:             BOOST_MPL_ASSERT((is_same<AccumulatorSet, void>));
Chris@16: 
Chris@16:             typedef
Chris@16:                 accumulator_wrapper<
Chris@16:                     typename mpl::apply2<typename Feature::impl, Sample, Weight>::type
Chris@16:                   , Feature
Chris@16:                 >
Chris@16:             accumulator_type;
Chris@16: 
Chris@16:             typedef
Chris@16:                 typename mpl::if_<
Chris@16:                     typename Feature::is_weight_accumulator
Chris@16:                   , accumulator_wrapper<impl::external_impl<accumulator_type, tag::weights>, Feature>
Chris@16:                   , accumulator_type
Chris@16:                 >::type
Chris@16:             type;
Chris@16:         };
Chris@16: 
Chris@16:         // BUGBUG work around an MPL bug wrt map insertion
Chris@16:         template<typename FeatureMap, typename Feature>
Chris@16:         struct insert_feature
Chris@16:           : mpl::eval_if<
Chris@16:                 mpl::has_key<FeatureMap, typename feature_of<Feature>::type>
Chris@16:               , mpl::identity<FeatureMap>
Chris@16:               , mpl::insert<FeatureMap, mpl::pair<typename feature_of<Feature>::type, Feature> >
Chris@16:             >
Chris@16:         {
Chris@16:         };
Chris@16: 
Chris@16:         template<typename FeatureMap, typename Feature, typename Weight>
Chris@16:         struct insert_dependencies
Chris@16:           : mpl::fold<
Chris@16:                 as_feature_list<typename Feature::dependencies, Weight>
Chris@16:               , FeatureMap
Chris@16:               , insert_dependencies<
Chris@16:                     insert_feature<mpl::_1, mpl::_2>
Chris@16:                   , mpl::_2
Chris@16:                   , Weight
Chris@16:                 >
Chris@16:             >
Chris@16:         {
Chris@16:         };
Chris@16: 
Chris@16:         template<typename FeatureMap, typename Features, typename Weight>
Chris@16:         struct insert_sequence
Chris@16:           : mpl::fold< // BUGBUG should use insert_range, but doesn't seem to work for maps
Chris@16:                 as_feature_list<Features, Weight>
Chris@16:               , FeatureMap
Chris@16:               , insert_feature<mpl::_1, mpl::_2>
Chris@16:             >
Chris@16:         {
Chris@16:         };
Chris@16: 
Chris@16:         template<typename Features, typename Sample, typename Weight>
Chris@16:         struct make_accumulator_tuple
Chris@16:         {
Chris@16:             typedef
Chris@16:                 typename mpl::fold<
Chris@16:                     as_feature_list<Features, Weight>
Chris@16:                   , mpl::map0<>
Chris@16:                   , mpl::if_<
Chris@16:                         mpl::is_sequence<mpl::_2>
Chris@16:                       , insert_sequence<mpl::_1, mpl::_2, Weight>
Chris@16:                       , insert_feature<mpl::_1, mpl::_2>
Chris@16:                     >
Chris@16:                 >::type
Chris@16:             feature_map;
Chris@16: 
Chris@16:             // for each element in the map, add its dependencies also
Chris@16:             typedef
Chris@16:                 typename mpl::fold<
Chris@16:                     feature_map
Chris@16:                   , feature_map
Chris@16:                   , insert_dependencies<mpl::_1, mpl::second<mpl::_2>, Weight>
Chris@16:                 >::type
Chris@16:             feature_map_with_dependencies;
Chris@16: 
Chris@16:             // turn the map into a vector so we can sort it
Chris@16:             typedef
Chris@16:                 typename mpl::insert_range<
Chris@16:                     mpl::vector<>
Chris@16:                   , mpl::end<mpl::vector<> >::type
Chris@16:                   , mpl::transform_view<feature_map_with_dependencies, mpl::second<mpl::_1> >
Chris@16:                 >::type
Chris@16:             feature_vector_with_dependencies;
Chris@16: 
Chris@16:             // sort the features according to which is derived from which
Chris@16:             typedef
Chris@16:                 typename mpl::sort<
Chris@16:                     feature_vector_with_dependencies
Chris@16:                   , is_dependent_on<mpl::_2, mpl::_1>
Chris@16:                 >::type
Chris@16:             sorted_feature_vector;
Chris@16: 
Chris@16:             // From the vector of features, construct a vector of accumulators
Chris@16:             typedef
Chris@16:                 typename mpl::transform<
Chris@16:                     sorted_feature_vector
Chris@16:                   , to_accumulator<mpl::_1, Sample, Weight>
Chris@16:                 >::type
Chris@16:             type;
Chris@16:         };
Chris@16: 
Chris@16:     } // namespace detail
Chris@16: 
Chris@16: }} // namespace boost::accumulators
Chris@16: 
Chris@16: #endif