minimal_iterable.hpp

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#ifndef BOOST_MPL11_TEST_MINIMAL_ITERABLE_HPP
#define BOOST_MPL11_TEST_MINIMAL_ITERABLE_HPP

#include <boost/mpl11/bool.hpp>
#include <boost/mpl11/core.hpp>
#include <boost/mpl11/iterable.hpp>


struct MinimalIterable;

template <typename ...xs>
struct minimal_iterable {
    using type = minimal_iterable;
    using mpl_datatype = MinimalIterable;
};

namespace boost { namespace mpl11 {
    template <>
    struct Iterable<MinimalIterable>
        : instantiate<Iterable>::with<MinimalIterable>
    {
        template <typename>
        struct head_impl;

        template <typename x, typename ...xs>
        struct head_impl<minimal_iterable<x, xs...>> : x { };


        template <typename>
        struct tail_impl;

        template <typename x, typename ...xs>
        struct tail_impl<minimal_iterable<x, xs...>>
            : minimal_iterable<xs...>
        { };


        template <typename>
        struct is_empty_impl;

        template <typename ...xs>
        struct is_empty_impl<minimal_iterable<xs...>>
            : bool_<sizeof...(xs) == 0>
        { };
    };
}} // end namespace boost::mpl11

#endif // !BOOST_MPL11_TEST_MINIMAL_ITERABLE_HPP