shift_operator.h

 
//          Copyright John McFarlane 2019.
// Distributed under the Boost Software License, Version 1.0.
//    (See accompanying file ../LICENSE_1_0.txt or copy at
//          http://www.boost.org/LICENSE_1_0.txt)
 
#if !defined(CNL_IMPL_WRAPPER_SHIFT_OPERATOR_H)
#define CNL_IMPL_WRAPPER_SHIFT_OPERATOR_H
 
#include "../custom_operator/native_tag.h"
#include "from_rep.h"
#include "is_wrapper.h"
#include "operator_helpers.h"
#include "tag_of.h"
#include "to_rep.h"
 
namespace cnl {
    // non-wrapper << wrapper
    // includes derived classes
    template<_impl::shift_op Operator, class Lhs, _impl::any_wrapper Rhs>
    requires(!_impl::is_wrapper<Lhs>) struct custom_operator<Operator, op_value<Lhs>, op_value<Rhs>> {
        [[nodiscard]] constexpr auto operator()(Lhs const& lhs, Rhs const& rhs) const
        {
            return Operator()(lhs, _impl::rep_of_t<Rhs>{_impl::to_rep(rhs)});
        }
    };
 
    // wrapper << non-wrapper
    template<_impl::shift_op Operator, _impl::any_wrapper Lhs, class Rhs>
    requires _impl::number_can_wrap<Lhs, Rhs>::value struct custom_operator<
            Operator, op_value<Lhs>, op_value<Rhs>> {
        [[nodiscard]] constexpr auto operator()(
                Lhs const& lhs, Rhs const& rhs) const
        {
            return _impl::from_rep<Lhs>(
                    custom_operator<Operator, op_value<_impl::rep_of_t<Lhs>, _impl::tag_of_t<Lhs>>, op_value<Rhs>>{}(
                            _impl::to_rep(lhs), rhs));
        }
    };
 
    // wrapper<int, Foo> << wrapper<int, Foo>
    // includes derived classes
    template<_impl::shift_op Operator, typename LhsRep, tag LhsTag, _impl::any_wrapper Rhs>
    struct custom_operator<
            Operator, op_value<_impl::wrapper<LhsRep, LhsTag>>, op_value<Rhs>> {
        [[nodiscard]] constexpr auto operator()(
                _impl::wrapper<LhsRep, LhsTag> const& lhs, Rhs const& rhs) const
        {
            return _impl::from_rep<_impl::wrapper<LhsRep, LhsTag>>(
                    custom_operator<
                            Operator, op_value<LhsRep, LhsTag>, op_value<_impl::rep_of_t<Rhs>>>{}(
                            _impl::to_rep(lhs), _impl::to_rep(rhs)));
        }
    };
}
 
#endif  // CNL_IMPL_WRAPPER_SHIFT_OPERATOR_H