definition.h

Go to the documentation of this file.

 
//          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_OPERATORS_GENERIC_OPERATORS_H)
#define CNL_IMPL_OPERATORS_GENERIC_OPERATORS_H
 
#include "../../arithmetic.h"
#include "../config.h"
#include "op.h"
#include "tag.h"
 
#include <type_traits>
 
namespace cnl {
    namespace _impl {
        struct native_tag;
 
        // cnl::_impl::wants_generic_ops
 
        // true iff T wants generic operator overloads
        template<class T>
        inline constexpr auto wants_generic_ops = false;
    }
 
    // cnl::op_value
 
    template<arithmetic Rep, tag Tag = _impl::native_tag>
    class op_value;
 
    namespace _impl {
        template<typename T>
        inline constexpr bool is_operand_specialization = false;
 
        template<arithmetic Rep, typename Tag>
        inline constexpr bool is_operand_specialization<op_value<Rep, Tag>> = true;
 
        template<typename T>
        concept operand_specialization = is_operand_specialization<T>;
    }
 
    // generic operators
 
    template<_impl::op Operator, _impl::operand_specialization... Operands>
    struct custom_operator;
 
    template<class ArchetypeTag, typename Initializer>
    struct deduction;
 
    template<_impl::compound_assign_op Operator, class LhsOperand, tag LhsTag, class RhsOperand, tag RhsTag>
    struct custom_operator<
            Operator,
            op_value<LhsOperand, LhsTag>,
            op_value<RhsOperand, RhsTag>> {
        constexpr auto& operator()(LhsOperand& lhs, RhsOperand const& rhs) const
        {
            using compound_assign_operator = cnl::custom_operator<
                    typename Operator::binary, op_value<LhsOperand, LhsTag>, op_value<RhsOperand, RhsTag>>;
            using compound_assign_operator_result = decltype(compound_assign_operator{}(lhs, rhs));
            using convert_operator = cnl::custom_operator<
                    _impl::convert_op,
                    op_value<compound_assign_operator_result, RhsTag>,
                    op_value<LhsOperand, LhsTag>>;
            return lhs = convert_operator{}(compound_assign_operator{}(lhs, rhs));
        }
    };
}
 
#endif  // CNL_IMPL_OPERATORS_GENERIC_OPERATORS_H