monoid.hpp

Go to the documentation of this file.

#ifndef BOOST_MPL11_MONOID_HPP
#define BOOST_MPL11_MONOID_HPP

#include <boost/mpl11/fwd/monoid.hpp>

#include <boost/mpl11/bool.hpp>
#include <boost/mpl11/core.hpp>
#include <boost/mpl11/detail/left_folds/variadic.hpp>


namespace boost { namespace mpl11 {
    template <typename Left, typename Right, typename>
    struct Monoid : false_ { };

    template <typename x1, typename x2, typename ...xn>
    struct plus
        : detail::left_folds::variadic<plus, x1, x2, xn...>
    { };

    template <typename x, typename y>
    struct plus<x, y> :
        Monoid<
            typename datatype<typename x::type>::type,
            typename datatype<typename y::type>::type
        >::template plus_impl<typename x::type, typename y::type>
    { };

    template <typename Datatype>
    struct zero : Monoid<Datatype>::template zero_impl<> { };
}} // end namespace boost::mpl11

#endif // !BOOST_MPL11_MONOID_HPP