// Copyright (C) 2018 T. Zachary Laine
//
// 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)
#include <boost/parser/parser.hpp>


using namespace boost::parser;

void compile_or_attribute()
{
    char const chars[] = "";
    auto first = std::begin(chars);
    auto const last = std::end(chars);

    // scalar and eps
    {
        constexpr auto parser = int_ | eps;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(
            std::is_same_v<attr_t, std::optional<std::optional<int>>>);
        static_assert(std::is_same_v<
                      attribute_t<
                          decltype(BOOST_PARSER_SUBRANGE(first, last)),
                          decltype(parser)>,
                      std::optional<int>>);
    }

    // scalar | scalar
    {
        constexpr auto parser = char_ | char_;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(std::is_same_v<attr_t, std::optional<char>>);
        static_assert(std::is_same_v<
                      attribute_t<
                          decltype(BOOST_PARSER_SUBRANGE(first, last)),
                          decltype(parser)>,
                      char>);
    }
    {
        constexpr auto parser = char_ | char_ | eps;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(
            std::is_same_v<attr_t, std::optional<std::optional<char>>>);
        static_assert(std::is_same_v<
                      attribute_t<
                          decltype(BOOST_PARSER_SUBRANGE(first, last)),
                          decltype(parser)>,
                      std::optional<char>>);
    }
    {
        constexpr auto parser = int_ | char_;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(
            std::is_same_v<attr_t, std::optional<std::variant<int, char>>>);
        static_assert(std::is_same_v<
                      attribute_t<
                          decltype(BOOST_PARSER_SUBRANGE(first, last)),
                          decltype(parser)>,
                      std::variant<int, char>>);
    }
    {
        constexpr auto parser = int_ | char_ | eps;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(std::is_same_v<
                      attr_t,
                      std::optional<std::optional<std::variant<int, char>>>>);
        static_assert(std::is_same_v<
                      attribute_t<
                          decltype(BOOST_PARSER_SUBRANGE(first, last)),
                          decltype(parser)>,
                      std::optional<std::variant<int, char>>>);
    }

    // -scalar | -scalar
    {
        constexpr auto parser = -char_ | -char_;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(
            std::is_same_v<attr_t, std::optional<std::optional<char>>>);
        static_assert(std::is_same_v<
                      attribute_t<
                          decltype(BOOST_PARSER_SUBRANGE(first, last)),
                          decltype(parser)>,
                      std::optional<char>>);
    }
    {
        constexpr auto parser = -char_ | -char_ | eps;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(
            std::is_same_v<attr_t, std::optional<std::optional<char>>>);
        static_assert(std::is_same_v<
                      attribute_t<
                          decltype(BOOST_PARSER_SUBRANGE(first, last)),
                          decltype(parser)>,
                      std::optional<char>>);
    }
    {
        constexpr auto parser = -int_ | -char_;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(
            std::is_same_v<
                attr_t,
                std::optional<
                    std::variant<std::optional<int>, std::optional<char>>>>);
        static_assert(std::is_same_v<
                      attribute_t<
                          decltype(BOOST_PARSER_SUBRANGE(first, last)),
                          decltype(parser)>,
                      std::variant<std::optional<int>, std::optional<char>>>);
    }
    {
        constexpr auto parser = -int_ | -char_ | eps;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(
            std::is_same_v<
                attr_t,
                std::optional<std::optional<
                    std::variant<std::optional<int>, std::optional<char>>>>>);
        static_assert(
            std::is_same_v<
                attribute_t<
                    decltype(BOOST_PARSER_SUBRANGE(first, last)),
                    decltype(parser)>,
                std::optional<
                    std::variant<std::optional<int>, std::optional<char>>>>);
    }

    // seq<T> | seq<T>
    {
        constexpr auto parser = *char_ | *char_;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(std::is_same_v<attr_t, std::optional<std::string>>);
        static_assert(std::is_same_v<
                      attribute_t<
                          decltype(BOOST_PARSER_SUBRANGE(first, last)),
                          decltype(parser)>,
                      std::string>);
    }
    {
        constexpr auto parser = *char_ | *char_ | eps;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(
            std::is_same_v<attr_t, std::optional<std::optional<std::string>>>);
        static_assert(std::is_same_v<
                      attribute_t<
                          decltype(BOOST_PARSER_SUBRANGE(first, last)),
                          decltype(parser)>,
                      std::optional<std::string>>);
    }
    {
        constexpr auto parser = *string("str") | *string("str");
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(
            std::is_same_v<attr_t, std::optional<std::vector<std::string>>>);
        static_assert(std::is_same_v<
                      attribute_t<
                          decltype(BOOST_PARSER_SUBRANGE(first, last)),
                          decltype(parser)>,
                      std::vector<std::string>>);
    }
    {
        constexpr auto parser = *string("str") | *string("str") | eps;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(std::is_same_v<
                      attr_t,
                      std::optional<std::optional<std::vector<std::string>>>>);
        static_assert(std::is_same_v<
                      attribute_t<
                          decltype(BOOST_PARSER_SUBRANGE(first, last)),
                          decltype(parser)>,
                      std::optional<std::vector<std::string>>>);
    }

    // seq<T> | seq<U>
    {
        constexpr auto parser = *char_ | *string("str");
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(
            std::is_same_v<
                attr_t,
                std::optional<
                    std::variant<std::string, std::vector<std::string>>>>);
    }
    {
        constexpr auto parser = *char_ | *string("str") | eps;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(
            std::is_same_v<
                attr_t,
                std::optional<std::optional<
                    std::variant<std::string, std::vector<std::string>>>>>);
    }

    // seq<T> | T
    {
        constexpr auto parser = *char_ | char_;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(std::is_same_v<
                      attr_t,
                      std::optional<std::variant<std::string, char>>>);
    }
    {
        constexpr auto parser = *char_ | char_ | eps;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(
            std::is_same_v<
                attr_t,
                std::optional<std::optional<std::variant<std::string, char>>>>);
    }
    {
        constexpr auto parser = *string("str") | char_;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(
            std::is_same_v<
                attr_t,
                std::optional<std::variant<std::vector<std::string>, char>>>);
    }
    {
        constexpr auto parser = *string("str") | char_ | eps;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(std::is_same_v<
                      attr_t,
                      std::optional<std::optional<
                          std::variant<std::vector<std::string>, char>>>>);
    }

    // T | seq<T>
    {
        constexpr auto parser = char_ | *char_;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(std::is_same_v<
                      attr_t,
                      std::optional<std::variant<char, std::string>>>);
    }
    {
        constexpr auto parser = char_ | *char_ | eps;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(
            std::is_same_v<
                attr_t,
                std::optional<std::optional<std::variant<char, std::string>>>>);
    }
    {
        constexpr auto parser = char_ | *string("str");
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(
            std::is_same_v<
                attr_t,
                std::optional<std::variant<char, std::vector<std::string>>>>);
    }
    {
        constexpr auto parser = char_ | *string("str") | eps;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(std::is_same_v<
                      attr_t,
                      std::optional<std::optional<
                          std::variant<char, std::vector<std::string>>>>>);
    }

    // seq<T> | std::optional<T>
    {
        constexpr auto parser = *char_ | -char_;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(
            std::is_same_v<
                attr_t,
                std::optional<std::variant<std::string, std::optional<char>>>>);
    }
    {
        constexpr auto parser = *char_ | -char_ | eps;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(std::is_same_v<
                      attr_t,
                      std::optional<std::optional<
                          std::variant<std::string, std::optional<char>>>>>);
    }
    {
        constexpr auto parser = *string("str") | -char_;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(std::is_same_v<
                      attr_t,
                      std::optional<std::variant<
                          std::vector<std::string>,
                          std::optional<char>>>>);
    }
    {
        constexpr auto parser = *string("str") | -char_ | eps;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(std::is_same_v<
                      attr_t,
                      std::optional<std::optional<std::variant<
                          std::vector<std::string>,
                          std::optional<char>>>>>);
    }

    // std::optional<T> | seq<T>
    {
        constexpr auto parser = -char_ | *char_;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(
            std::is_same_v<
                attr_t,
                std::optional<std::variant<std::optional<char>, std::string>>>);
    }
    {
        constexpr auto parser = -char_ | *char_ | eps;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(std::is_same_v<
                      attr_t,
                      std::optional<std::optional<
                          std::variant<std::optional<char>, std::string>>>>);
    }
    {
        constexpr auto parser = -char_ | *string("str");
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(std::is_same_v<
                      attr_t,
                      std::optional<std::variant<
                          std::optional<char>,
                          std::vector<std::string>>>>);
    }
    {
        constexpr auto parser = -char_ | *string("str") | eps;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(std::is_same_v<
                      attr_t,
                      std::optional<std::optional<std::variant<
                          std::optional<char>,
                          std::vector<std::string>>>>>);
    }

    // or grouping
    {
        constexpr auto parser = (-char_ | *string("str")) | eps;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(std::is_same_v<
                      attr_t,
                      std::optional<std::optional<std::variant<
                          std::optional<char>,
                          std::vector<std::string>>>>>);
    }
    {
        constexpr auto parser = -char_ | (*string("str") | eps);
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(std::is_same_v<
                      attr_t,
                      std::optional<std::optional<std::variant<
                          std::optional<char>,
                          std::vector<std::string>>>>>);
    }
    {
        constexpr auto parser = int_ | string("str") | double_;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(std::is_same_v<
                      attr_t,
                      std::optional<std::variant<int, std::string, double>>>);
    }
    {
        constexpr auto parser = (int_ | string("str")) | double_;
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(std::is_same_v<
                      attr_t,
                      std::optional<std::variant<int, std::string, double>>>);
    }
    {
        constexpr auto parser = int_ | (string("str") | double_);
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(std::is_same_v<
                      attr_t,
                      std::optional<std::variant<int, std::string, double>>>);
    }
    {
        constexpr auto parser = (int_ | string("str")) | (double_ | float_);
        using attr_t = decltype(prefix_parse(first, last, parser));
        static_assert(
            std::is_same_v<
                attr_t,
                std::optional<std::variant<int, std::string, double, float>>>);
    }
}