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// Copyright 2017 Elias Kosunen
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// This file is a part of scnlib:
// https://github.com/eliaskosunen/scnlib
#ifndef SCN_TUPLE_RETURN_TUPLE_RETURN_H
#define SCN_TUPLE_RETURN_TUPLE_RETURN_H
#include "../scan/vscan.h"
#include "util.h"
namespace scn {
SCN_BEGIN_NAMESPACE
namespace dummy {
}
/**
* Alternative interface for scanning, returning values as a tuple, instead
* of taking them by reference.
*
* It's highly recommended to use this interface only with C++17 or later,
* as structured bindings make it way more ergonomic.
*
* Compared to the regular scan interface, the performance of this interface
* is the same (generated code is virtually identical with optimizations
* enabled), but the compile time is slower.
*
* Values scanned by this function still need to be default-constructible.
* To scan a non-default-constructible value, use \c scn::optional
*
* \param r Input range
* \param f Format string to use
*
* \return Tuple, where the first element is the scan result, and the
* remaining elements are the scanned values.
*/
#if SCN_DOXYGEN
template <typename... Args, typename Range, typename Format>
auto scan_tuple(Range&& r, Format f)
-> std::tuple<detail::scan_result_for_range<Range>, Args...>;
#else
template <typename... Args, typename Range, typename Format>
SCN_NODISCARD auto scan_tuple(Range&& r, Format f)
-> std::tuple<detail::scan_result_for_range<Range>, Args...>
{
using result = detail::scan_result_for_range<Range>;
using range_type = typename result::wrapped_range_type;
using context_type = basic_context<range_type>;
using parse_context_type =
basic_parse_context<typename context_type::locale_type>;
using char_type = typename range_type::char_type;
auto range = wrap(SCN_FWD(r));
auto scanfn = [&range, &f](Args&... a) {
auto args = make_args<context_type, parse_context_type>(a...);
return vscan(SCN_MOVE(range), basic_string_view<char_type>(f),
{args});
};
std::tuple<Args...> values{Args{}...};
auto ret = detail::apply(scanfn, values);
return std::tuple_cat(
std::tuple<result>{detail::wrap_result(wrapped_error{ret.err},
detail::range_tag<Range>{},
SCN_MOVE(ret.range))},
SCN_MOVE(values));
}
#endif
/**
* Equivalent to `scan_tuple`, except uses `vscan_default` under the hood.
*/
#if SCN_DOXYGEN
template <typename... Args, typename Range>
auto scan_tuple_default(Range&& r)
-> std::tuple<detail::scan_result_for_range<Range>, Args...>;
#else
template <typename... Args, typename Range>
SCN_NODISCARD auto scan_tuple_default(Range&& r)
-> std::tuple<detail::scan_result_for_range<Range>, Args...>
{
using result = detail::scan_result_for_range<Range>;
using range_type = typename result::wrapped_range_type;
using context_type = basic_context<range_type>;
using parse_context_type =
basic_empty_parse_context<typename context_type::locale_type>;
auto range = wrap(SCN_FWD(r));
auto scanfn = [&range](Args&... a) {
auto args = make_args<context_type, parse_context_type>(a...);
return vscan_default(SCN_MOVE(range),
static_cast<int>(sizeof...(Args)), {args});
};
std::tuple<Args...> values{Args{}...};
auto ret = detail::apply(scanfn, values);
return std::tuple_cat(
std::tuple<result>{detail::wrap_result(wrapped_error{ret.err},
detail::range_tag<Range>{},
SCN_MOVE(ret.range))},
SCN_MOVE(values));
}
#endif
SCN_END_NAMESPACE
} // namespace scn
#endif
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