include/fmt/compile.h - platform/external/fmtlib - Git at Google

 // Formatting library for C++ - experimental format string compilation
 //
 // Copyright (c) 2012 - present, Victor Zverovich and fmt contributors
 // All rights reserved.
 //
 // For the license information refer to format.h.

 #ifndef FMT_COMPILE_H_
 #define FMT_COMPILE_H_

 #include "format.h"

 FMT_BEGIN_NAMESPACE
 namespace detail {

 template <typename Char, typename InputIt>
 FMT_CONSTEXPR inline counting_iterator copy_str(InputIt begin, InputIt end,
                                                 counting_iterator it) {
   return it + (end - begin);
 }

 // A compile-time string which is compiled into fast formatting code.
 class compiled_string {};

 template <typename S>
 struct is_compiled_string : std::is_base_of<compiled_string, S> {};

 /**
   \rst
   Converts a string literal *s* into a format string that will be parsed at
   compile time and converted into efficient formatting code. Requires C++17
   ``constexpr if`` compiler support.

   **Example**::

     // Converts 42 into std::string using the most efficient method and no
     // runtime format string processing.
     std::string s = fmt::format(FMT_COMPILE("{}"), 42);
   \endrst
  */
 #if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 #  define FMT_COMPILE(s) \
     FMT_STRING_IMPL(s, fmt::detail::compiled_string, explicit)
 #else
 #  define FMT_COMPILE(s) FMT_STRING(s)
 #endif

 #if FMT_USE_NONTYPE_TEMPLATE_ARGS
 template <typename Char, size_t N,
           fmt::detail_exported::fixed_string<Char, N> Str>
 struct udl_compiled_string : compiled_string {
   using char_type = Char;
   explicit constexpr operator basic_string_view<char_type>() const {
     return {Str.data, N - 1};
   }
 };
 #endif

 template <typename T, typename... Tail>
 const T& first(const T& value, const Tail&...) {
   return value;
 }

 #if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 template <typename... Args> struct type_list {};

 // Returns a reference to the argument at index N from [first, rest...].
 template <int N, typename T, typename... Args>
 constexpr const auto& get([[maybe_unused]] const T& first,
                           [[maybe_unused]] const Args&... rest) {
   static_assert(N < 1 + sizeof...(Args), "index is out of bounds");
   if constexpr (N == 0)
     return first;
   else
     return detail::get<N - 1>(rest...);
 }

 template <typename Char, typename... Args>
 constexpr int get_arg_index_by_name(basic_string_view<Char> name,
                                     type_list<Args...>) {
   return get_arg_index_by_name<Args...>(name);
 }

 template <int N, typename> struct get_type_impl;

 template <int N, typename... Args> struct get_type_impl<N, type_list<Args...>> {
   using type =
       remove_cvref_t<decltype(detail::get<N>(std::declval<Args>()...))>;
 };

 template <int N, typename T>
 using get_type = typename get_type_impl<N, T>::type;

 template <typename T> struct is_compiled_format : std::false_type {};

 template <typename Char> struct text {
   basic_string_view<Char> data;
   using char_type = Char;

   template <typename OutputIt, typename... Args>
   constexpr OutputIt format(OutputIt out, const Args&...) const {
     return write<Char>(out, data);
   }
 };

 template <typename Char>
 struct is_compiled_format<text<Char>> : std::true_type {};

 template <typename Char>
 constexpr text<Char> make_text(basic_string_view<Char> s, size_t pos,
                                size_t size) {
   return {{&s[pos], size}};
 }

 template <typename Char> struct code_unit {
   Char value;
   using char_type = Char;

   template <typename OutputIt, typename... Args>
   constexpr OutputIt format(OutputIt out, const Args&...) const {
     *out++ = value;
     return out;
   }
 };

 // This ensures that the argument type is convertible to `const T&`.
 template <typename T, int N, typename... Args>
 constexpr const T& get_arg_checked(const Args&... args) {
   const auto& arg = detail::get<N>(args...);
   if constexpr (detail::is_named_arg<remove_cvref_t<decltype(arg)>>()) {
     return arg.value;
   } else {
     return arg;
   }
 }

 template <typename Char>
 struct is_compiled_format<code_unit<Char>> : std::true_type {};

 // A replacement field that refers to argument N.
 template <typename Char, typename T, int N> struct field {
   using char_type = Char;

   template <typename OutputIt, typename... Args>
   constexpr OutputIt format(OutputIt out, const Args&... args) const {
     const T& arg = get_arg_checked<T, N>(args...);
     if constexpr (std::is_convertible_v<T, basic_string_view<Char>>) {
       auto s = basic_string_view<Char>(arg);
       return copy_str<Char>(s.begin(), s.end(), out);
     }
     return write<Char>(out, arg);
   }
 };

 template <typename Char, typename T, int N>
 struct is_compiled_format<field<Char, T, N>> : std::true_type {};

 // A replacement field that refers to argument with name.
 template <typename Char> struct runtime_named_field {
   using char_type = Char;
   basic_string_view<Char> name;

   template <typename OutputIt, typename T>
   constexpr static bool try_format_argument(
       OutputIt& out,
       // [[maybe_unused]] due to unused-but-set-parameter warning in GCC 7,8,9
       [[maybe_unused]] basic_string_view<Char> arg_name, const T& arg) {
     if constexpr (is_named_arg<typename std::remove_cv<T>::type>::value) {
       if (arg_name == arg.name) {
         out = write<Char>(out, arg.value);
         return true;
       }
     }
     return false;
   }

   template <typename OutputIt, typename... Args>
   constexpr OutputIt format(OutputIt out, const Args&... args) const {
     bool found = (try_format_argument(out, name, args) || ...);
     if (!found) {
       FMT_THROW(format_error("argument with specified name is not found"));
     }
     return out;
   }
 };

 template <typename Char>
 struct is_compiled_format<runtime_named_field<Char>> : std::true_type {};

 // A replacement field that refers to argument N and has format specifiers.
 template <typename Char, typename T, int N> struct spec_field {
   using char_type = Char;
   formatter<T, Char> fmt;

   template <typename OutputIt, typename... Args>
   constexpr FMT_INLINE OutputIt format(OutputIt out,
                                        const Args&... args) const {
     const auto& vargs =
         fmt::make_format_args<basic_format_context<OutputIt, Char>>(args...);
     basic_format_context<OutputIt, Char> ctx(out, vargs);
     return fmt.format(get_arg_checked<T, N>(args...), ctx);
   }
 };

 template <typename Char, typename T, int N>
 struct is_compiled_format<spec_field<Char, T, N>> : std::true_type {};

 template <typename L, typename R> struct concat {
   L lhs;
   R rhs;
   using char_type = typename L::char_type;

   template <typename OutputIt, typename... Args>
   constexpr OutputIt format(OutputIt out, const Args&... args) const {
     out = lhs.format(out, args...);
     return rhs.format(out, args...);
   }
 };

 template <typename L, typename R>
 struct is_compiled_format<concat<L, R>> : std::true_type {};

 template <typename L, typename R>
 constexpr concat<L, R> make_concat(L lhs, R rhs) {
   return {lhs, rhs};
 }

 struct unknown_format {};

 template <typename Char>
 constexpr size_t parse_text(basic_string_view<Char> str, size_t pos) {
   for (size_t size = str.size(); pos != size; ++pos) {
     if (str[pos] == '{' || str[pos] == '}') break;
   }
   return pos;
 }

 template <typename Args, size_t POS, int ID, typename S>
 constexpr auto compile_format_string(S format_str);

 template <typename Args, size_t POS, int ID, typename T, typename S>
 constexpr auto parse_tail(T head, S format_str) {
   if constexpr (POS !=
                 basic_string_view<typename S::char_type>(format_str).size()) {
     constexpr auto tail = compile_format_string<Args, POS, ID>(format_str);
     if constexpr (std::is_same<remove_cvref_t<decltype(tail)>,
                                unknown_format>())
       return tail;
     else
       return make_concat(head, tail);
   } else {
     return head;
   }
 }

 template <typename T, typename Char> struct parse_specs_result {
   formatter<T, Char> fmt;
   size_t end;
   int next_arg_id;
 };

 enum { manual_indexing_id = -1 };

 template <typename T, typename Char>
 constexpr parse_specs_result<T, Char> parse_specs(basic_string_view<Char> str,
                                                   size_t pos, int next_arg_id) {
   str.remove_prefix(pos);
   auto ctx =
       compile_parse_context<Char>(str, max_value<int>(), nullptr, next_arg_id);
   auto f = formatter<T, Char>();
   auto end = f.parse(ctx);
   return {f, pos + fmt::detail::to_unsigned(end - str.data()),
           next_arg_id == 0 ? manual_indexing_id : ctx.next_arg_id()};
 }

 template <typename Char> struct arg_id_handler {
   arg_ref<Char> arg_id;

   constexpr int on_auto() {
     FMT_ASSERT(false, "handler cannot be used with automatic indexing");
     return 0;
   }
   constexpr int on_index(int id) {
     arg_id = arg_ref<Char>(id);
     return 0;
   }
   constexpr int on_name(basic_string_view<Char> id) {
     arg_id = arg_ref<Char>(id);
     return 0;
   }
 };

 template <typename Char> struct parse_arg_id_result {
   arg_ref<Char> arg_id;
   const Char* arg_id_end;
 };

 template <int ID, typename Char>
 constexpr auto parse_arg_id(const Char* begin, const Char* end) {
   auto handler = arg_id_handler<Char>{arg_ref<Char>{}};
   auto arg_id_end = parse_arg_id(begin, end, handler);
   return parse_arg_id_result<Char>{handler.arg_id, arg_id_end};
 }

 template <typename T, typename Enable = void> struct field_type {
   using type = remove_cvref_t<T>;
 };

 template <typename T>
 struct field_type<T, enable_if_t<detail::is_named_arg<T>::value>> {
   using type = remove_cvref_t<decltype(T::value)>;
 };

 template <typename T, typename Args, size_t END_POS, int ARG_INDEX, int NEXT_ID,
           typename S>
 constexpr auto parse_replacement_field_then_tail(S format_str) {
   using char_type = typename S::char_type;
   constexpr auto str = basic_string_view<char_type>(format_str);
   constexpr char_type c = END_POS != str.size() ? str[END_POS] : char_type();
   if constexpr (c == '}') {
     return parse_tail<Args, END_POS + 1, NEXT_ID>(
         field<char_type, typename field_type<T>::type, ARG_INDEX>(),
         format_str);
   } else if constexpr (c != ':') {
     FMT_THROW(format_error("expected ':'"));
   } else {
     constexpr auto result = parse_specs<typename field_type<T>::type>(
         str, END_POS + 1, NEXT_ID == manual_indexing_id ? 0 : NEXT_ID);
     if constexpr (result.end >= str.size() || str[result.end] != '}') {
       FMT_THROW(format_error("expected '}'"));
       return 0;
     } else {
       return parse_tail<Args, result.end + 1, result.next_arg_id>(
           spec_field<char_type, typename field_type<T>::type, ARG_INDEX>{
               result.fmt},
           format_str);
     }
   }
 }

 // Compiles a non-empty format string and returns the compiled representation
 // or unknown_format() on unrecognized input.
 template <typename Args, size_t POS, int ID, typename S>
 constexpr auto compile_format_string(S format_str) {
   using char_type = typename S::char_type;
   constexpr auto str = basic_string_view<char_type>(format_str);
   if constexpr (str[POS] == '{') {
     if constexpr (POS + 1 == str.size())
       FMT_THROW(format_error("unmatched '{' in format string"));
     if constexpr (str[POS + 1] == '{') {
       return parse_tail<Args, POS + 2, ID>(make_text(str, POS, 1), format_str);
     } else if constexpr (str[POS + 1] == '}' || str[POS + 1] == ':') {
       static_assert(ID != manual_indexing_id,
                     "cannot switch from manual to automatic argument indexing");
       constexpr auto next_id =
           ID != manual_indexing_id ? ID + 1 : manual_indexing_id;
       return parse_replacement_field_then_tail<get_type<ID, Args>, Args,
                                                POS + 1, ID, next_id>(
           format_str);
     } else {
       constexpr auto arg_id_result =
           parse_arg_id<ID>(str.data() + POS + 1, str.data() + str.size());
       constexpr auto arg_id_end_pos = arg_id_result.arg_id_end - str.data();
       constexpr char_type c =
           arg_id_end_pos != str.size() ? str[arg_id_end_pos] : char_type();
       static_assert(c == '}' || c == ':', "missing '}' in format string");
       if constexpr (arg_id_result.arg_id.kind == arg_id_kind::index) {
         static_assert(
             ID == manual_indexing_id || ID == 0,
             "cannot switch from automatic to manual argument indexing");
         constexpr auto arg_index = arg_id_result.arg_id.val.index;
         return parse_replacement_field_then_tail<get_type<arg_index, Args>,
                                                  Args, arg_id_end_pos,
                                                  arg_index, manual_indexing_id>(
             format_str);
       } else if constexpr (arg_id_result.arg_id.kind == arg_id_kind::name) {
         constexpr auto arg_index =
             get_arg_index_by_name(arg_id_result.arg_id.val.name, Args{});
         if constexpr (arg_index >= 0) {
           constexpr auto next_id =
               ID != manual_indexing_id ? ID + 1 : manual_indexing_id;
           return parse_replacement_field_then_tail<
               decltype(get_type<arg_index, Args>::value), Args, arg_id_end_pos,
               arg_index, next_id>(format_str);
         } else if constexpr (c == '}') {
           return parse_tail<Args, arg_id_end_pos + 1, ID>(
               runtime_named_field<char_type>{arg_id_result.arg_id.val.name},
               format_str);
         } else if constexpr (c == ':') {
           return unknown_format();  // no type info for specs parsing
         }
       }
     }
   } else if constexpr (str[POS] == '}') {
     if constexpr (POS + 1 == str.size())
       FMT_THROW(format_error("unmatched '}' in format string"));
     return parse_tail<Args, POS + 2, ID>(make_text(str, POS, 1), format_str);
   } else {
     constexpr auto end = parse_text(str, POS + 1);
     if constexpr (end - POS > 1) {
       return parse_tail<Args, end, ID>(make_text(str, POS, end - POS),
                                        format_str);
     } else {
       return parse_tail<Args, end, ID>(code_unit<char_type>{str[POS]},
                                        format_str);
     }
   }
 }

 template <typename... Args, typename S,
           FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
 constexpr auto compile(S format_str) {
   constexpr auto str = basic_string_view<typename S::char_type>(format_str);
   if constexpr (str.size() == 0) {
     return detail::make_text(str, 0, 0);
   } else {
     constexpr auto result =
         detail::compile_format_string<detail::type_list<Args...>, 0, 0>(
             format_str);
     return result;
   }
 }
 #endif  // defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 }  // namespace detail

 FMT_BEGIN_EXPORT

 #if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)

 template <typename CompiledFormat, typename... Args,
           typename Char = typename CompiledFormat::char_type,
           FMT_ENABLE_IF(detail::is_compiled_format<CompiledFormat>::value)>
 FMT_INLINE std::basic_string<Char> format(const CompiledFormat& cf,
                                           const Args&... args) {
   auto s = std::basic_string<Char>();
   cf.format(std::back_inserter(s), args...);
   return s;
 }

 template <typename OutputIt, typename CompiledFormat, typename... Args,
           FMT_ENABLE_IF(detail::is_compiled_format<CompiledFormat>::value)>
 constexpr FMT_INLINE OutputIt format_to(OutputIt out, const CompiledFormat& cf,
                                         const Args&... args) {
   return cf.format(out, args...);
 }

 template <typename S, typename... Args,
           FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
 FMT_INLINE std::basic_string<typename S::char_type> format(const S&,
                                                            Args&&... args) {
   if constexpr (std::is_same<typename S::char_type, char>::value) {
     constexpr auto str = basic_string_view<typename S::char_type>(S());
     if constexpr (str.size() == 2 && str[0] == '{' && str[1] == '}') {
       const auto& first = detail::first(args...);
       if constexpr (detail::is_named_arg<
                         remove_cvref_t<decltype(first)>>::value) {
         return fmt::to_string(first.value);
       } else {
         return fmt::to_string(first);
       }
     }
   }
   constexpr auto compiled = detail::compile<Args...>(S());
   if constexpr (std::is_same<remove_cvref_t<decltype(compiled)>,
                              detail::unknown_format>()) {
     return fmt::format(
         static_cast<basic_string_view<typename S::char_type>>(S()),
         std::forward<Args>(args)...);
   } else {
     return fmt::format(compiled, std::forward<Args>(args)...);
   }
 }

 template <typename OutputIt, typename S, typename... Args,
           FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
 FMT_CONSTEXPR OutputIt format_to(OutputIt out, const S&, Args&&... args) {
   constexpr auto compiled = detail::compile<Args...>(S());
   if constexpr (std::is_same<remove_cvref_t<decltype(compiled)>,
                              detail::unknown_format>()) {
     return fmt::format_to(
         out, static_cast<basic_string_view<typename S::char_type>>(S()),
         std::forward<Args>(args)...);
   } else {
     return fmt::format_to(out, compiled, std::forward<Args>(args)...);
   }
 }
 #endif

 template <typename OutputIt, typename S, typename... Args,
           FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
 format_to_n_result<OutputIt> format_to_n(OutputIt out, size_t n,
                                          const S& format_str, Args&&... args) {
   using traits = detail::fixed_buffer_traits;
   auto buf = detail::iterator_buffer<OutputIt, char, traits>(out, n);
   format_to(std::back_inserter(buf), format_str, std::forward<Args>(args)...);
   return {buf.out(), buf.count()};
 }

 template <typename S, typename... Args,
           FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
 FMT_CONSTEXPR20 size_t formatted_size(const S& format_str,
                                       const Args&... args) {
   return fmt::format_to(detail::counting_iterator(), format_str, args...)
       .count();
 }

 template <typename S, typename... Args,
           FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
 void print(std::FILE* f, const S& format_str, const Args&... args) {
   memory_buffer buffer;
   fmt::format_to(std::back_inserter(buffer), format_str, args...);
   detail::print(f, {buffer.data(), buffer.size()});
 }

 template <typename S, typename... Args,
           FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
 void print(const S& format_str, const Args&... args) {
   print(stdout, format_str, args...);
 }

 #if FMT_USE_NONTYPE_TEMPLATE_ARGS
 inline namespace literals {
 template <detail_exported::fixed_string Str> constexpr auto operator""_cf() {
   using char_t = remove_cvref_t<decltype(Str.data[0])>;
   return detail::udl_compiled_string<char_t, sizeof(Str.data) / sizeof(char_t),
                                      Str>();
 }
 }  // namespace literals
 #endif

 FMT_END_EXPORT
 FMT_END_NAMESPACE

 #endif  // FMT_COMPILE_H_
	// Formatting library for C++ - experimental format string compilation
	//
	// Copyright (c) 2012 - present, Victor Zverovich and fmt contributors
	// All rights reserved.
	//
	// For the license information refer to format.h.

	#ifndef FMT_COMPILE_H_
	#define FMT_COMPILE_H_

	#include "format.h"

	FMT_BEGIN_NAMESPACE
	namespace detail {

	template <typename Char, typename InputIt>
	FMT_CONSTEXPR inline counting_iterator copy_str(InputIt begin, InputIt end,
	counting_iterator it) {
	return it + (end - begin);
	}

	// A compile-time string which is compiled into fast formatting code.
	class compiled_string {};

	template <typename S>
	struct is_compiled_string : std::is_base_of<compiled_string, S> {};

	/**
	\rst
	Converts a string literal s into a format string that will be parsed at
	compile time and converted into efficient formatting code. Requires C++17
	``constexpr if`` compiler support.

	Example::

	// Converts 42 into std::string using the most efficient method and no
	// runtime format string processing.
	std::string s = fmt::format(FMT_COMPILE("{}"), 42);
	\endrst
	*/
	#if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
	# define FMT_COMPILE(s) \
	FMT_STRING_IMPL(s, fmt::detail::compiled_string, explicit)
	#else
	# define FMT_COMPILE(s) FMT_STRING(s)
	#endif

	#if FMT_USE_NONTYPE_TEMPLATE_ARGS
	template <typename Char, size_t N,
	fmt::detail_exported::fixed_string<Char, N> Str>
	struct udl_compiled_string : compiled_string {
	using char_type = Char;
	explicit constexpr operator basic_string_view<char_type>() const {
	return {Str.data, N - 1};
	}
	};
	#endif

	template <typename T, typename... Tail>
	const T& first(const T& value, const Tail&...) {
	return value;
	}

	#if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
	template <typename... Args> struct type_list {};

	// Returns a reference to the argument at index N from [first, rest...].
	template <int N, typename T, typename... Args>
	constexpr const auto& get([[maybe_unused]] const T& first,
	[[maybe_unused]] const Args&... rest) {
	static_assert(N < 1 + sizeof...(Args), "index is out of bounds");
	if constexpr (N == 0)
	return first;
	else
	return detail::get<N - 1>(rest...);
	}

	template <typename Char, typename... Args>
	constexpr int get_arg_index_by_name(basic_string_view<Char> name,
	type_list<Args...>) {
	return get_arg_index_by_name<Args...>(name);
	}

	template <int N, typename> struct get_type_impl;

	template <int N, typename... Args> struct get_type_impl<N, type_list<Args...>> {
	using type =
	remove_cvref_t<decltype(detail::get<N>(std::declval<Args>()...))>;
	};

	template <int N, typename T>
	using get_type = typename get_type_impl<N, T>::type;

	template <typename T> struct is_compiled_format : std::false_type {};

	template <typename Char> struct text {
	basic_string_view<Char> data;
	using char_type = Char;

	template <typename OutputIt, typename... Args>
	constexpr OutputIt format(OutputIt out, const Args&...) const {
	return write<Char>(out, data);
	}
	};

	template <typename Char>
	struct is_compiled_format<text<Char>> : std::true_type {};

	template <typename Char>
	constexpr text<Char> make_text(basic_string_view<Char> s, size_t pos,
	size_t size) {
	return {{&s[pos], size}};
	}

	template <typename Char> struct code_unit {
	Char value;
	using char_type = Char;

	template <typename OutputIt, typename... Args>
	constexpr OutputIt format(OutputIt out, const Args&...) const {
	*out++ = value;
	return out;
	}
	};

	// This ensures that the argument type is convertible to `const T&`.
	template <typename T, int N, typename... Args>
	constexpr const T& get_arg_checked(const Args&... args) {
	const auto& arg = detail::get<N>(args...);
	if constexpr (detail::is_named_arg<remove_cvref_t<decltype(arg)>>()) {
	return arg.value;
	} else {
	return arg;
	}
	}

	template <typename Char>
	struct is_compiled_format<code_unit<Char>> : std::true_type {};

	// A replacement field that refers to argument N.
	template <typename Char, typename T, int N> struct field {
	using char_type = Char;

	template <typename OutputIt, typename... Args>
	constexpr OutputIt format(OutputIt out, const Args&... args) const {
	const T& arg = get_arg_checked<T, N>(args...);
	if constexpr (std::is_convertible_v<T, basic_string_view<Char>>) {
	auto s = basic_string_view<Char>(arg);
	return copy_str<Char>(s.begin(), s.end(), out);
	}
	return write<Char>(out, arg);
	}
	};

	template <typename Char, typename T, int N>
	struct is_compiled_format<field<Char, T, N>> : std::true_type {};

	// A replacement field that refers to argument with name.
	template <typename Char> struct runtime_named_field {
	using char_type = Char;
	basic_string_view<Char> name;

	template <typename OutputIt, typename T>
	constexpr static bool try_format_argument(
	OutputIt& out,
	// [[maybe_unused]] due to unused-but-set-parameter warning in GCC 7,8,9
	[[maybe_unused]] basic_string_view<Char> arg_name, const T& arg) {
	if constexpr (is_named_arg<typename std::remove_cv<T>::type>::value) {
	if (arg_name == arg.name) {
	out = write<Char>(out, arg.value);
	return true;
	}
	}
	return false;
	}

	template <typename OutputIt, typename... Args>
	constexpr OutputIt format(OutputIt out, const Args&... args) const {
	bool found = (try_format_argument(out, name, args) \|\| ...);
	if (!found) {
	FMT_THROW(format_error("argument with specified name is not found"));
	}
	return out;
	}
	};

	template <typename Char>
	struct is_compiled_format<runtime_named_field<Char>> : std::true_type {};

	// A replacement field that refers to argument N and has format specifiers.
	template <typename Char, typename T, int N> struct spec_field {
	using char_type = Char;
	formatter<T, Char> fmt;

	template <typename OutputIt, typename... Args>
	constexpr FMT_INLINE OutputIt format(OutputIt out,
	const Args&... args) const {
	const auto& vargs =
	fmt::make_format_args<basic_format_context<OutputIt, Char>>(args...);
	basic_format_context<OutputIt, Char> ctx(out, vargs);
	return fmt.format(get_arg_checked<T, N>(args...), ctx);
	}
	};

	template <typename Char, typename T, int N>
	struct is_compiled_format<spec_field<Char, T, N>> : std::true_type {};

	template <typename L, typename R> struct concat {
	L lhs;
	R rhs;
	using char_type = typename L::char_type;

	template <typename OutputIt, typename... Args>
	constexpr OutputIt format(OutputIt out, const Args&... args) const {
	out = lhs.format(out, args...);
	return rhs.format(out, args...);
	}
	};

	template <typename L, typename R>
	struct is_compiled_format<concat<L, R>> : std::true_type {};

	template <typename L, typename R>
	constexpr concat<L, R> make_concat(L lhs, R rhs) {
	return {lhs, rhs};
	}

	struct unknown_format {};

	template <typename Char>
	constexpr size_t parse_text(basic_string_view<Char> str, size_t pos) {
	for (size_t size = str.size(); pos != size; ++pos) {
	if (str[pos] == '{' \|\| str[pos] == '}') break;
	}
	return pos;
	}

	template <typename Args, size_t POS, int ID, typename S>
	constexpr auto compile_format_string(S format_str);

	template <typename Args, size_t POS, int ID, typename T, typename S>
	constexpr auto parse_tail(T head, S format_str) {
	if constexpr (POS !=
	basic_string_view<typename S::char_type>(format_str).size()) {
	constexpr auto tail = compile_format_string<Args, POS, ID>(format_str);
	if constexpr (std::is_same<remove_cvref_t<decltype(tail)>,
	unknown_format>())
	return tail;
	else
	return make_concat(head, tail);
	} else {
	return head;
	}
	}

	template <typename T, typename Char> struct parse_specs_result {
	formatter<T, Char> fmt;
	size_t end;
	int next_arg_id;
	};

	enum { manual_indexing_id = -1 };

	template <typename T, typename Char>
	constexpr parse_specs_result<T, Char> parse_specs(basic_string_view<Char> str,
	size_t pos, int next_arg_id) {
	str.remove_prefix(pos);
	auto ctx =
	compile_parse_context<Char>(str, max_value<int>(), nullptr, next_arg_id);
	auto f = formatter<T, Char>();
	auto end = f.parse(ctx);
	return {f, pos + fmt::detail::to_unsigned(end - str.data()),
	next_arg_id == 0 ? manual_indexing_id : ctx.next_arg_id()};
	}

	template <typename Char> struct arg_id_handler {
	arg_ref<Char> arg_id;

	constexpr int on_auto() {
	FMT_ASSERT(false, "handler cannot be used with automatic indexing");
	return 0;
	}
	constexpr int on_index(int id) {
	arg_id = arg_ref<Char>(id);
	return 0;
	}
	constexpr int on_name(basic_string_view<Char> id) {
	arg_id = arg_ref<Char>(id);
	return 0;
	}
	};

	template <typename Char> struct parse_arg_id_result {
	arg_ref<Char> arg_id;
	const Char* arg_id_end;
	};

	template <int ID, typename Char>
	constexpr auto parse_arg_id(const Char* begin, const Char* end) {
	auto handler = arg_id_handler<Char>{arg_ref<Char>{}};
	auto arg_id_end = parse_arg_id(begin, end, handler);
	return parse_arg_id_result<Char>{handler.arg_id, arg_id_end};
	}

	template <typename T, typename Enable = void> struct field_type {
	using type = remove_cvref_t<T>;
	};

	template <typename T>
	struct field_type<T, enable_if_t<detail::is_named_arg<T>::value>> {
	using type = remove_cvref_t<decltype(T::value)>;
	};

	template <typename T, typename Args, size_t END_POS, int ARG_INDEX, int NEXT_ID,
	typename S>
	constexpr auto parse_replacement_field_then_tail(S format_str) {
	using char_type = typename S::char_type;
	constexpr auto str = basic_string_view<char_type>(format_str);
	constexpr char_type c = END_POS != str.size() ? str[END_POS] : char_type();
	if constexpr (c == '}') {
	return parse_tail<Args, END_POS + 1, NEXT_ID>(
	field<char_type, typename field_type<T>::type, ARG_INDEX>(),
	format_str);
	} else if constexpr (c != ':') {
	FMT_THROW(format_error("expected ':'"));
	} else {
	constexpr auto result = parse_specs<typename field_type<T>::type>(
	str, END_POS + 1, NEXT_ID == manual_indexing_id ? 0 : NEXT_ID);
	if constexpr (result.end >= str.size() \|\| str[result.end] != '}') {
	FMT_THROW(format_error("expected '}'"));
	return 0;
	} else {
	return parse_tail<Args, result.end + 1, result.next_arg_id>(
	spec_field<char_type, typename field_type<T>::type, ARG_INDEX>{
	result.fmt},
	format_str);
	}
	}
	}

	// Compiles a non-empty format string and returns the compiled representation
	// or unknown_format() on unrecognized input.
	template <typename Args, size_t POS, int ID, typename S>
	constexpr auto compile_format_string(S format_str) {
	using char_type = typename S::char_type;
	constexpr auto str = basic_string_view<char_type>(format_str);
	if constexpr (str[POS] == '{') {
	if constexpr (POS + 1 == str.size())
	FMT_THROW(format_error("unmatched '{' in format string"));
	if constexpr (str[POS + 1] == '{') {
	return parse_tail<Args, POS + 2, ID>(make_text(str, POS, 1), format_str);
	} else if constexpr (str[POS + 1] == '}' \|\| str[POS + 1] == ':') {
	static_assert(ID != manual_indexing_id,
	"cannot switch from manual to automatic argument indexing");
	constexpr auto next_id =
	ID != manual_indexing_id ? ID + 1 : manual_indexing_id;
	return parse_replacement_field_then_tail<get_type<ID, Args>, Args,
	POS + 1, ID, next_id>(
	format_str);
	} else {
	constexpr auto arg_id_result =
	parse_arg_id<ID>(str.data() + POS + 1, str.data() + str.size());
	constexpr auto arg_id_end_pos = arg_id_result.arg_id_end - str.data();
	constexpr char_type c =
	arg_id_end_pos != str.size() ? str[arg_id_end_pos] : char_type();
	static_assert(c == '}' \|\| c == ':', "missing '}' in format string");
	if constexpr (arg_id_result.arg_id.kind == arg_id_kind::index) {
	static_assert(
	ID == manual_indexing_id \|\| ID == 0,
	"cannot switch from automatic to manual argument indexing");
	constexpr auto arg_index = arg_id_result.arg_id.val.index;
	return parse_replacement_field_then_tail<get_type<arg_index, Args>,
	Args, arg_id_end_pos,
	arg_index, manual_indexing_id>(
	format_str);
	} else if constexpr (arg_id_result.arg_id.kind == arg_id_kind::name) {
	constexpr auto arg_index =
	get_arg_index_by_name(arg_id_result.arg_id.val.name, Args{});
	if constexpr (arg_index >= 0) {
	constexpr auto next_id =
	ID != manual_indexing_id ? ID + 1 : manual_indexing_id;
	return parse_replacement_field_then_tail<
	decltype(get_type<arg_index, Args>::value), Args, arg_id_end_pos,
	arg_index, next_id>(format_str);
	} else if constexpr (c == '}') {
	return parse_tail<Args, arg_id_end_pos + 1, ID>(
	runtime_named_field<char_type>{arg_id_result.arg_id.val.name},
	format_str);
	} else if constexpr (c == ':') {
	return unknown_format(); // no type info for specs parsing
	}
	}
	}
	} else if constexpr (str[POS] == '}') {
	if constexpr (POS + 1 == str.size())
	FMT_THROW(format_error("unmatched '}' in format string"));
	return parse_tail<Args, POS + 2, ID>(make_text(str, POS, 1), format_str);
	} else {
	constexpr auto end = parse_text(str, POS + 1);
	if constexpr (end - POS > 1) {
	return parse_tail<Args, end, ID>(make_text(str, POS, end - POS),
	format_str);
	} else {
	return parse_tail<Args, end, ID>(code_unit<char_type>{str[POS]},
	format_str);
	}
	}
	}

	template <typename... Args, typename S,
	FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
	constexpr auto compile(S format_str) {
	constexpr auto str = basic_string_view<typename S::char_type>(format_str);
	if constexpr (str.size() == 0) {
	return detail::make_text(str, 0, 0);
	} else {
	constexpr auto result =
	detail::compile_format_string<detail::type_list<Args...>, 0, 0>(
	format_str);
	return result;
	}
	}
	#endif // defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
	} // namespace detail

	FMT_BEGIN_EXPORT

	#if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)

	template <typename CompiledFormat, typename... Args,
	typename Char = typename CompiledFormat::char_type,
	FMT_ENABLE_IF(detail::is_compiled_format<CompiledFormat>::value)>
	FMT_INLINE std::basic_string<Char> format(const CompiledFormat& cf,
	const Args&... args) {
	auto s = std::basic_string<Char>();
	cf.format(std::back_inserter(s), args...);
	return s;
	}

	template <typename OutputIt, typename CompiledFormat, typename... Args,
	FMT_ENABLE_IF(detail::is_compiled_format<CompiledFormat>::value)>
	constexpr FMT_INLINE OutputIt format_to(OutputIt out, const CompiledFormat& cf,
	const Args&... args) {
	return cf.format(out, args...);
	}

	template <typename S, typename... Args,
	FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
	FMT_INLINE std::basic_string<typename S::char_type> format(const S&,
	Args&&... args) {
	if constexpr (std::is_same<typename S::char_type, char>::value) {
	constexpr auto str = basic_string_view<typename S::char_type>(S());
	if constexpr (str.size() == 2 && str[0] == '{' && str[1] == '}') {
	const auto& first = detail::first(args...);
	if constexpr (detail::is_named_arg<
	remove_cvref_t<decltype(first)>>::value) {
	return fmt::to_string(first.value);
	} else {
	return fmt::to_string(first);
	}
	}
	}
	constexpr auto compiled = detail::compile<Args...>(S());
	if constexpr (std::is_same<remove_cvref_t<decltype(compiled)>,
	detail::unknown_format>()) {
	return fmt::format(
	static_cast<basic_string_view<typename S::char_type>>(S()),
	std::forward<Args>(args)...);
	} else {
	return fmt::format(compiled, std::forward<Args>(args)...);
	}
	}

	template <typename OutputIt, typename S, typename... Args,
	FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
	FMT_CONSTEXPR OutputIt format_to(OutputIt out, const S&, Args&&... args) {
	constexpr auto compiled = detail::compile<Args...>(S());
	if constexpr (std::is_same<remove_cvref_t<decltype(compiled)>,
	detail::unknown_format>()) {
	return fmt::format_to(
	out, static_cast<basic_string_view<typename S::char_type>>(S()),
	std::forward<Args>(args)...);
	} else {
	return fmt::format_to(out, compiled, std::forward<Args>(args)...);
	}
	}
	#endif

	template <typename OutputIt, typename S, typename... Args,
	FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
	format_to_n_result<OutputIt> format_to_n(OutputIt out, size_t n,
	const S& format_str, Args&&... args) {
	using traits = detail::fixed_buffer_traits;
	auto buf = detail::iterator_buffer<OutputIt, char, traits>(out, n);
	format_to(std::back_inserter(buf), format_str, std::forward<Args>(args)...);
	return {buf.out(), buf.count()};
	}

	template <typename S, typename... Args,
	FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
	FMT_CONSTEXPR20 size_t formatted_size(const S& format_str,
	const Args&... args) {
	return fmt::format_to(detail::counting_iterator(), format_str, args...)
	.count();
	}

	template <typename S, typename... Args,
	FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
	void print(std::FILE* f, const S& format_str, const Args&... args) {
	memory_buffer buffer;
	fmt::format_to(std::back_inserter(buffer), format_str, args...);
	detail::print(f, {buffer.data(), buffer.size()});
	}

	template <typename S, typename... Args,
	FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
	void print(const S& format_str, const Args&... args) {
	print(stdout, format_str, args...);
	}

	#if FMT_USE_NONTYPE_TEMPLATE_ARGS
	inline namespace literals {
	template <detail_exported::fixed_string Str> constexpr auto operator""_cf() {
	using char_t = remove_cvref_t<decltype(Str.data[0])>;
	return detail::udl_compiled_string<char_t, sizeof(Str.data) / sizeof(char_t),
	Str>();
	}
	} // namespace literals
	#endif

	FMT_END_EXPORT
	FMT_END_NAMESPACE

	#endif // FMT_COMPILE_H_