to_string.hpp

Go to the documentation of this file.

// SPDX-FileCopyrightText: 2006-2024, Knut Reinert & Freie Universität Berlin
// SPDX-FileCopyrightText: 2016-2024, Knut Reinert & MPI für molekulare Genetik
// SPDX-License-Identifier: BSD-3-Clause
 
#pragma once
 
#include <sstream>
 
#include <sharg/concept.hpp>
#include <sharg/detail/concept.hpp>
 
namespace sharg::detail
{
 
static std::string const supported_exports =
#if SHARG_HAS_TDL
    "[html, man, ctd, cwl]";
#else
    "[html, man]";
#endif
 
template <typename container_t>
concept is_ostreamable_view = std::ranges::view<container_t> && ostreamable<std::ranges::range_value_t<container_t>>;
 
template <typename... value_types>
    requires (ostreamable<value_types> && ...)
std::string to_string(value_types &&... values)
{
    std::stringstream stream;
 
    auto print = [&stream](auto && val)
    {
        using value_t = std::remove_cvref_t<decltype(val)>;
 
        // When passing a `std::vector<std::string> | std::views::transform(...)` which returns `std::quoted(str)` for
        // each element, the `std::quoted`'s return value does not model a range, but is ostreamable.
        if constexpr (is_container_option<value_t> || is_ostreamable_view<value_t>)
        {
            if (val.empty())
            {
                stream << "[]";
            }
            else
            {
                stream << '[';
                auto it = val.begin();
                stream << *it++;
                for (; it != val.end(); ++it)
                    stream << ", " << *it;
                stream << ']';
            }
        }
        else if constexpr (std::is_same_v<value_t, int8_t> || std::is_same_v<value_t, uint8_t>)
        {
            stream << static_cast<int16_t>(val);
        }
        else
        {
            stream << val;
        }
    };
 
    (print(std::forward<value_types>(values)), ...);
 
    return stream.str();
}
 
} // namespace sharg::detail