// Formatting library for C++ - the core API
	//
	// Copyright (c) 2012 - present, Victor Zverovich
	// All rights reserved.
	//
	// For the license information refer to format.h.
	
	#ifndef FMT_CORE_H_
	#define FMT_CORE_H_
	
	#include <cstdio>  // std::FILE
	#include <cstring>
	#include <iterator>
	#include <string>
	#include <type_traits>
	
	// The fmt library version in the form major * 10000 + minor * 100 + patch.
	#define FMT_VERSION 60102
	
	#ifdef __has_feature
	#  define FMT_HAS_FEATURE(x) __has_feature(x)
	#else
	#  define FMT_HAS_FEATURE(x) 0
	#endif
	
	#if defined(__has_include) && !defined(__INTELLISENSE__) && \
	    !(defined(__INTEL_COMPILER) && __INTEL_COMPILER < 1600)
	#  define FMT_HAS_INCLUDE(x) __has_include(x)
	#else
	#  define FMT_HAS_INCLUDE(x) 0
	#endif
	
	#ifdef __has_cpp_attribute
	#  define FMT_HAS_CPP_ATTRIBUTE(x) __has_cpp_attribute(x)
	#else
	#  define FMT_HAS_CPP_ATTRIBUTE(x) 0
	#endif
	
	#if defined(__GNUC__) && !defined(__clang__)
	#  define FMT_GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
	#else
	#  define FMT_GCC_VERSION 0
	#endif
	
	#if __cplusplus >= 201103L || defined(__GXX_EXPERIMENTAL_CXX0X__)
	#  define FMT_HAS_GXX_CXX11 FMT_GCC_VERSION
	#else
	#  define FMT_HAS_GXX_CXX11 0
	#endif
	
	#ifdef __NVCC__
	#  define FMT_NVCC __NVCC__
	#else
	#  define FMT_NVCC 0
	#endif
	
	#ifdef _MSC_VER
	#  define FMT_MSC_VER _MSC_VER
	#else
	#  define FMT_MSC_VER 0
	#endif
	
	// Check if relaxed C++14 constexpr is supported.
	// GCC doesn't allow throw in constexpr until version 6 (bug 67371).
	#ifndef FMT_USE_CONSTEXPR
	#  define FMT_USE_CONSTEXPR                                           \
	    (FMT_HAS_FEATURE(cxx_relaxed_constexpr) || FMT_MSC_VER >= 1910 || \
	     (FMT_GCC_VERSION >= 600 && __cplusplus >= 201402L)) &&           \
	        !FMT_NVCC
	#endif
	#if FMT_USE_CONSTEXPR
	#  define FMT_CONSTEXPR constexpr
	#  define FMT_CONSTEXPR_DECL constexpr
	#else
	#  define FMT_CONSTEXPR inline
	#  define FMT_CONSTEXPR_DECL
	#endif
	
	#ifndef FMT_OVERRIDE
	#  if FMT_HAS_FEATURE(cxx_override) || \
	      (FMT_GCC_VERSION >= 408 && FMT_HAS_GXX_CXX11) || FMT_MSC_VER >= 1900
	#    define FMT_OVERRIDE override
	#  else
	#    define FMT_OVERRIDE
	#  endif
	#endif
	
	// Check if exceptions are disabled.
	#ifndef FMT_EXCEPTIONS
	#  if (defined(__GNUC__) && !defined(__EXCEPTIONS)) || \
	      FMT_MSC_VER && !_HAS_EXCEPTIONS
	#    define FMT_EXCEPTIONS 0
	#  else
	#    define FMT_EXCEPTIONS 1
	#  endif
	#endif
	
	// Define FMT_USE_NOEXCEPT to make fmt use noexcept (C++11 feature).
	#ifndef FMT_USE_NOEXCEPT
	#  define FMT_USE_NOEXCEPT 0
	#endif
	
	#if FMT_USE_NOEXCEPT || FMT_HAS_FEATURE(cxx_noexcept) || \
	    (FMT_GCC_VERSION >= 408 && FMT_HAS_GXX_CXX11) || FMT_MSC_VER >= 1900
	#  define FMT_DETECTED_NOEXCEPT noexcept
	#  define FMT_HAS_CXX11_NOEXCEPT 1
	#else
	#  define FMT_DETECTED_NOEXCEPT throw()
	#  define FMT_HAS_CXX11_NOEXCEPT 0
	#endif
	
	#ifndef FMT_NOEXCEPT
	#  if FMT_EXCEPTIONS || FMT_HAS_CXX11_NOEXCEPT
	#    define FMT_NOEXCEPT FMT_DETECTED_NOEXCEPT
	#  else
	#    define FMT_NOEXCEPT
	#  endif
	#endif
	
	// [[noreturn]] is disabled on MSVC because of bogus unreachable code warnings.
	#if FMT_EXCEPTIONS && FMT_HAS_CPP_ATTRIBUTE(noreturn) && !FMT_MSC_VER
	#  define FMT_NORETURN [[noreturn]]
	#else
	#  define FMT_NORETURN
	#endif
	
	#ifndef FMT_DEPRECATED
	#  if (FMT_HAS_CPP_ATTRIBUTE(deprecated) && __cplusplus >= 201402L) || \
	      FMT_MSC_VER >= 1900
	#    define FMT_DEPRECATED [[deprecated]]
	#  else
	#    if defined(__GNUC__) || defined(__clang__)
	#      define FMT_DEPRECATED __attribute__((deprecated))
	#    elif FMT_MSC_VER
	#      define FMT_DEPRECATED __declspec(deprecated)
	#    else
	#      define FMT_DEPRECATED /* deprecated */
	#    endif
	#  endif
	#endif
	
	// Workaround broken [[deprecated]] in the Intel compiler and NVCC.
	#if defined(__INTEL_COMPILER) || FMT_NVCC
	#  define FMT_DEPRECATED_ALIAS
	#else
	#  define FMT_DEPRECATED_ALIAS FMT_DEPRECATED
	#endif
	
	#ifndef FMT_BEGIN_NAMESPACE
	#  if FMT_HAS_FEATURE(cxx_inline_namespaces) || FMT_GCC_VERSION >= 404 || \
	      FMT_MSC_VER >= 1900
	#    define FMT_INLINE_NAMESPACE inline namespace
	#    define FMT_END_NAMESPACE \
	      }                       \
	      }
	#  else
	#    define FMT_INLINE_NAMESPACE namespace
	#    define FMT_END_NAMESPACE \
	      }                       \
	      using namespace v6;     \
	      }
	#  endif
	#  define FMT_BEGIN_NAMESPACE \
	    namespace fmt {           \
	    FMT_INLINE_NAMESPACE v6 {
	#endif
	
	#if !defined(FMT_HEADER_ONLY) && defined(_WIN32)
	#  ifdef FMT_EXPORT
	#    define FMT_API __declspec(dllexport)
	#  elif defined(FMT_SHARED)
	#    define FMT_API __declspec(dllimport)
	#    define FMT_EXTERN_TEMPLATE_API FMT_API
	#  endif
	#endif
	#ifndef FMT_API
	#  define FMT_API
	#endif
	#ifndef FMT_EXTERN_TEMPLATE_API
	#  define FMT_EXTERN_TEMPLATE_API
	#endif
	
	#ifndef FMT_HEADER_ONLY
	#  define FMT_EXTERN extern
	#else
	#  define FMT_EXTERN
	#endif
	
	// libc++ supports string_view in pre-c++17.
	#if (FMT_HAS_INCLUDE(<string_view>) &&                       \
	     (__cplusplus > 201402L || defined(_LIBCPP_VERSION))) || \
	    (defined(_MSVC_LANG) && _MSVC_LANG > 201402L && _MSC_VER >= 1910)
	#  include <string_view>
	#  define FMT_USE_STRING_VIEW
	#elif FMT_HAS_INCLUDE("experimental/string_view") && __cplusplus >= 201402L
	#  include <experimental/string_view>
	#  define FMT_USE_EXPERIMENTAL_STRING_VIEW
	#endif
	
	FMT_BEGIN_NAMESPACE
	
	// Implementations of enable_if_t and other types for pre-C++14 systems.
	template <bool B, class T = void>
	using enable_if_t = typename std::enable_if<B, T>::type;
	template <bool B, class T, class F>
	using conditional_t = typename std::conditional<B, T, F>::type;
	template <bool B> using bool_constant = std::integral_constant<bool, B>;
	template <typename T>
	using remove_reference_t = typename std::remove_reference<T>::type;
	template <typename T>
	using remove_const_t = typename std::remove_const<T>::type;
	template <typename T>
	using remove_cvref_t = typename std::remove_cv<remove_reference_t<T>>::type;
	
	struct monostate {};
	
	// An enable_if helper to be used in template parameters which results in much
	// shorter symbols: https://godbolt.org/z/sWw4vP. Extra parentheses are needed
	// to workaround a bug in MSVC 2019 (see #1140 and #1186).
	#define FMT_ENABLE_IF(...) enable_if_t<(__VA_ARGS__), int> = 0
	
	namespace internal {
	
	// A workaround for gcc 4.8 to make void_t work in a SFINAE context.
	template <typename... Ts> struct void_t_impl { using type = void; };
	
	FMT_API void assert_fail(const char* file, int line, const char* message);
	
	#ifndef FMT_ASSERT
	#  ifdef NDEBUG
	#    define FMT_ASSERT(condition, message)
	#  else
	#    define FMT_ASSERT(condition, message) \
	      ((condition)                         \
	           ? void()                        \
	           : fmt::internal::assert_fail(__FILE__, __LINE__, (message)))
	#  endif
	#endif
	
	#if defined(FMT_USE_STRING_VIEW)
	template <typename Char> using std_string_view = std::basic_string_view<Char>;
	#elif defined(FMT_USE_EXPERIMENTAL_STRING_VIEW)
	template <typename Char>
	using std_string_view = std::experimental::basic_string_view<Char>;
	#else
	template <typename T> struct std_string_view {};
	#endif
	
	#ifdef FMT_USE_INT128
	// Do nothing.
	#elif defined(__SIZEOF_INT128__)
	#  define FMT_USE_INT128 1
	using int128_t = __int128_t;
	using uint128_t = __uint128_t;
	#else
	#  define FMT_USE_INT128 0
	#endif
	#if !FMT_USE_INT128
	struct int128_t {};
	struct uint128_t {};
	#endif
	
	// Casts a nonnegative integer to unsigned.
	template <typename Int>
	FMT_CONSTEXPR typename std::make_unsigned<Int>::type to_unsigned(Int value) {
	  FMT_ASSERT(value >= 0, "negative value");
	  return static_cast<typename std::make_unsigned<Int>::type>(value);
	}
	}  // namespace internal
	
	template <typename... Ts>
	using void_t = typename internal::void_t_impl<Ts...>::type;
	
	/**
	  An implementation of ``std::basic_string_view`` for pre-C++17. It provides a
	  subset of the API. ``fmt::basic_string_view`` is used for format strings even
	  if ``std::string_view`` is available to prevent issues when a library is
	  compiled with a different ``-std`` option than the client code (which is not
	  recommended).
	 */
	template <typename Char> class basic_string_view {
	 private:
	  const Char* data_;
	  size_t size_;
	
	 public:
	  using char_type = Char;
	  using iterator = const Char*;
	
	  FMT_CONSTEXPR basic_string_view() FMT_NOEXCEPT : data_(nullptr), size_(0) {}
	
	  /** Constructs a string reference object from a C string and a size. */
	  FMT_CONSTEXPR basic_string_view(const Char* s, size_t count) FMT_NOEXCEPT
	      : data_(s),
	        size_(count) {}
	
	  /**
	    \rst
	    Constructs a string reference object from a C string computing
	    the size with ``std::char_traits<Char>::length``.
	    \endrst
	   */
	  basic_string_view(const Char* s)
	      : data_(s), size_(std::char_traits<Char>::length(s)) {}
	
	  /** Constructs a string reference from a ``std::basic_string`` object. */
	  template <typename Traits, typename Alloc>
	  FMT_CONSTEXPR basic_string_view(
	      const std::basic_string<Char, Traits, Alloc>& s) FMT_NOEXCEPT
	      : data_(s.data()),
	        size_(s.size()) {}
	
	  template <
	      typename S,
	      FMT_ENABLE_IF(std::is_same<S, internal::std_string_view<Char>>::value)>
	  FMT_CONSTEXPR basic_string_view(S s) FMT_NOEXCEPT : data_(s.data()),
	                                                      size_(s.size()) {}
	
	  /** Returns a pointer to the string data. */
	  FMT_CONSTEXPR const Char* data() const { return data_; }
	
	  /** Returns the string size. */
	  FMT_CONSTEXPR size_t size() const { return size_; }
	
	  FMT_CONSTEXPR iterator begin() const { return data_; }
	  FMT_CONSTEXPR iterator end() const { return data_ + size_; }
	
	  FMT_CONSTEXPR const Char& operator[](size_t pos) const { return data_[pos]; }
	
	  FMT_CONSTEXPR void remove_prefix(size_t n) {
	    data_ += n;
	    size_ -= n;
	  }
	
	  // Lexicographically compare this string reference to other.
	  int compare(basic_string_view other) const {
	    size_t str_size = size_ < other.size_ ? size_ : other.size_;
	    int result = std::char_traits<Char>::compare(data_, other.data_, str_size);
	    if (result == 0)
	      result = size_ == other.size_ ? 0 : (size_ < other.size_ ? -1 : 1);
	    return result;
	  }
	
	  friend bool operator==(basic_string_view lhs, basic_string_view rhs) {
	    return lhs.compare(rhs) == 0;
	  }
	  friend bool operator!=(basic_string_view lhs, basic_string_view rhs) {
	    return lhs.compare(rhs) != 0;
	  }
	  friend bool operator<(basic_string_view lhs, basic_string_view rhs) {
	    return lhs.compare(rhs) < 0;
	  }
	  friend bool operator<=(basic_string_view lhs, basic_string_view rhs) {
	    return lhs.compare(rhs) <= 0;
	  }
	  friend bool operator>(basic_string_view lhs, basic_string_view rhs) {
	    return lhs.compare(rhs) > 0;
	  }
	  friend bool operator>=(basic_string_view lhs, basic_string_view rhs) {
	    return lhs.compare(rhs) >= 0;
	  }
	};
	
	using string_view = basic_string_view<char>;
	using wstring_view = basic_string_view<wchar_t>;
	
	#ifndef __cpp_char8_t
	// A UTF-8 code unit type.
	enum char8_t : unsigned char {};
	#endif
	
	/** Specifies if ``T`` is a character type. Can be specialized by users. */
	template <typename T> struct is_char : std::false_type {};
	template <> struct is_char<char> : std::true_type {};
	template <> struct is_char<wchar_t> : std::true_type {};
	template <> struct is_char<char8_t> : std::true_type {};
	template <> struct is_char<char16_t> : std::true_type {};
	template <> struct is_char<char32_t> : std::true_type {};
	
	/**
	  \rst
	  Returns a string view of `s`. In order to add custom string type support to
	  {fmt} provide an overload of `to_string_view` for it in the same namespace as
	  the type for the argument-dependent lookup to work.
	
	  **Example**::
	
	    namespace my_ns {
	    inline string_view to_string_view(const my_string& s) {
	      return {s.data(), s.length()};
	    }
	    }
	    std::string message = fmt::format(my_string("The answer is {}"), 42);
	  \endrst
	 */
	template <typename Char, FMT_ENABLE_IF(is_char<Char>::value)>
	inline basic_string_view<Char> to_string_view(const Char* s) {
	  return s;
	}
	
	template <typename Char, typename Traits, typename Alloc>
	inline basic_string_view<Char> to_string_view(
	    const std::basic_string<Char, Traits, Alloc>& s) {
	  return s;
	}
	
	template <typename Char>
	inline basic_string_view<Char> to_string_view(basic_string_view<Char> s) {
	  return s;
	}
	
	template <typename Char,
	          FMT_ENABLE_IF(!std::is_empty<internal::std_string_view<Char>>::value)>
	inline basic_string_view<Char> to_string_view(
	    internal::std_string_view<Char> s) {
	  return s;
	}
	
	// A base class for compile-time strings. It is defined in the fmt namespace to
	// make formatting functions visible via ADL, e.g. format(fmt("{}"), 42).
	struct compile_string {};
	
	template <typename S>
	struct is_compile_string : std::is_base_of<compile_string, S> {};
	
	template <typename S, FMT_ENABLE_IF(is_compile_string<S>::value)>
	constexpr basic_string_view<typename S::char_type> to_string_view(const S& s) {
	  return s;
	}
	
	namespace internal {
	void to_string_view(...);
	using fmt::v6::to_string_view;
	
	// Specifies whether S is a string type convertible to fmt::basic_string_view.
	// It should be a constexpr function but MSVC 2017 fails to compile it in
	// enable_if and MSVC 2015 fails to compile it as an alias template.
	template <typename S>
	struct is_string : std::is_class<decltype(to_string_view(std::declval<S>()))> {
	};
	
	template <typename S, typename = void> struct char_t_impl {};
	template <typename S> struct char_t_impl<S, enable_if_t<is_string<S>::value>> {
	  using result = decltype(to_string_view(std::declval<S>()));
	  using type = typename result::char_type;
	};
	
	struct error_handler {
	  FMT_CONSTEXPR error_handler() = default;
	  FMT_CONSTEXPR error_handler(const error_handler&) = default;
	
	  // This function is intentionally not constexpr to give a compile-time error.
	  FMT_NORETURN FMT_API void on_error(const char* message);
	};
	}  // namespace internal
	
	/** String's character type. */
	template <typename S> using char_t = typename internal::char_t_impl<S>::type;
	
	/**
	  \rst
	  Parsing context consisting of a format string range being parsed and an
	  argument counter for automatic indexing.
	
	  You can use one of the following type aliases for common character types:
	
	  +-----------------------+-------------------------------------+
	  | Type                  | Definition                          |
	  +=======================+=====================================+
	  | format_parse_context  | basic_format_parse_context<char>    |
	  +-----------------------+-------------------------------------+
	  | wformat_parse_context | basic_format_parse_context<wchar_t> |
	  +-----------------------+-------------------------------------+
	  \endrst
	 */
	template <typename Char, typename ErrorHandler = internal::error_handler>
	class basic_format_parse_context : private ErrorHandler {
	 private:
	  basic_string_view<Char> format_str_;
	  int next_arg_id_;
	
	 public:
	  using char_type = Char;
	  using iterator = typename basic_string_view<Char>::iterator;
	
	  explicit FMT_CONSTEXPR basic_format_parse_context(
	      basic_string_view<Char> format_str, ErrorHandler eh = ErrorHandler())
	      : ErrorHandler(eh), format_str_(format_str), next_arg_id_(0) {}
	
	  /**
	    Returns an iterator to the beginning of the format string range being
	    parsed.
	   */
	  FMT_CONSTEXPR iterator begin() const FMT_NOEXCEPT {
	    return format_str_.begin();
	  }
	
	  /**
	    Returns an iterator past the end of the format string range being parsed.
	   */
	  FMT_CONSTEXPR iterator end() const FMT_NOEXCEPT { return format_str_.end(); }
	
	  /** Advances the begin iterator to ``it``. */
	  FMT_CONSTEXPR void advance_to(iterator it) {
	    format_str_.remove_prefix(internal::to_unsigned(it - begin()));
	  }
	
	  /**
	    Reports an error if using the manual argument indexing; otherwise returns
	    the next argument index and switches to the automatic indexing.
	   */
	  FMT_CONSTEXPR int next_arg_id() {
	    if (next_arg_id_ >= 0) return next_arg_id_++;
	    on_error("cannot switch from manual to automatic argument indexing");
	    return 0;
	  }
	
	  /**
	    Reports an error if using the automatic argument indexing; otherwise
	    switches to the manual indexing.
	   */
	  FMT_CONSTEXPR void check_arg_id(int) {
	    if (next_arg_id_ > 0)
	      on_error("cannot switch from automatic to manual argument indexing");
	    else
	      next_arg_id_ = -1;
	  }
	
	  FMT_CONSTEXPR void check_arg_id(basic_string_view<Char>) {}
	
	  FMT_CONSTEXPR void on_error(const char* message) {
	    ErrorHandler::on_error(message);
	  }
	
	  FMT_CONSTEXPR ErrorHandler error_handler() const { return *this; }
	};
	
	using format_parse_context = basic_format_parse_context<char>;
	using wformat_parse_context = basic_format_parse_context<wchar_t>;
	
	template <typename Char, typename ErrorHandler = internal::error_handler>
	using basic_parse_context FMT_DEPRECATED_ALIAS =
	    basic_format_parse_context<Char, ErrorHandler>;
	using parse_context FMT_DEPRECATED_ALIAS = basic_format_parse_context<char>;
	using wparse_context FMT_DEPRECATED_ALIAS = basic_format_parse_context<wchar_t>;
	
	template <typename Context> class basic_format_arg;
	template <typename Context> class basic_format_args;
	
	// A formatter for objects of type T.
	template <typename T, typename Char = char, typename Enable = void>
	struct formatter {
	  // A deleted default constructor indicates a disabled formatter.
	  formatter() = delete;
	};
	
	template <typename T, typename Char, typename Enable = void>
	struct FMT_DEPRECATED convert_to_int
	    : bool_constant<!std::is_arithmetic<T>::value &&
	                    std::is_convertible<T, int>::value> {};
	
	// Specifies if T has an enabled formatter specialization. A type can be
	// formattable even if it doesn't have a formatter e.g. via a conversion.
	template <typename T, typename Context>
	using has_formatter =
	    std::is_constructible<typename Context::template formatter_type<T>>;
	
	namespace internal {
	
	/** A contiguous memory buffer with an optional growing ability. */
	template <typename T> class buffer {
	 private:
	  T* ptr_;
	  std::size_t size_;
	  std::size_t capacity_;
	
	 protected:
	  // Don't initialize ptr_ since it is not accessed to save a few cycles.
	  buffer(std::size_t sz) FMT_NOEXCEPT : size_(sz), capacity_(sz) {}
	
	  buffer(T* p = nullptr, std::size_t sz = 0, std::size_t cap = 0) FMT_NOEXCEPT
	      : ptr_(p),
	        size_(sz),
	        capacity_(cap) {}
	
	  /** Sets the buffer data and capacity. */
	  void set(T* buf_data, std::size_t buf_capacity) FMT_NOEXCEPT {
	    ptr_ = buf_data;
	    capacity_ = buf_capacity;
	  }
	
	  /** Increases the buffer capacity to hold at least *capacity* elements. */
	  virtual void grow(std::size_t capacity) = 0;
	
	 public:
	  using value_type = T;
	  using const_reference = const T&;
	
	  buffer(const buffer&) = delete;
	  void operator=(const buffer&) = delete;
	  virtual ~buffer() = default;
	
	  T* begin() FMT_NOEXCEPT { return ptr_; }
	  T* end() FMT_NOEXCEPT { return ptr_ + size_; }
	
	  /** Returns the size of this buffer. */
	  std::size_t size() const FMT_NOEXCEPT { return size_; }
	
	  /** Returns the capacity of this buffer. */
	  std::size_t capacity() const FMT_NOEXCEPT { return capacity_; }
	
	  /** Returns a pointer to the buffer data. */
	  T* data() FMT_NOEXCEPT { return ptr_; }
	
	  /** Returns a pointer to the buffer data. */
	  const T* data() const FMT_NOEXCEPT { return ptr_; }
	
	  /**
	    Resizes the buffer. If T is a POD type new elements may not be initialized.
	   */
	  void resize(std::size_t new_size) {
	    reserve(new_size);
	    size_ = new_size;
	  }
	
	  /** Clears this buffer. */
	  void clear() { size_ = 0; }
	
	  /** Reserves space to store at least *capacity* elements. */
	  void reserve(std::size_t new_capacity) {
	    if (new_capacity > capacity_) grow(new_capacity);
	  }
	
	  void push_back(const T& value) {
	    reserve(size_ + 1);
	    ptr_[size_++] = value;
	  }
	
	  /** Appends data to the end of the buffer. */
	  template <typename U> void append(const U* begin, const U* end);
	
	  T& operator[](std::size_t index) { return ptr_[index]; }
	  const T& operator[](std::size_t index) const { return ptr_[index]; }
	};
	
	// A container-backed buffer.
	template <typename Container>
	class container_buffer : public buffer<typename Container::value_type> {
	 private:
	  Container& container_;
	
	 protected:
	  void grow(std::size_t capacity) FMT_OVERRIDE {
	    container_.resize(capacity);
	    this->set(&container_[0], capacity);
	  }
	
	 public:
	  explicit container_buffer(Container& c)
	      : buffer<typename Container::value_type>(c.size()), container_(c) {}
	};
	
	// Extracts a reference to the container from back_insert_iterator.
	template <typename Container>
	inline Container& get_container(std::back_insert_iterator<Container> it) {
	  using bi_iterator = std::back_insert_iterator<Container>;
	  struct accessor : bi_iterator {
	    accessor(bi_iterator iter) : bi_iterator(iter) {}
	    using bi_iterator::container;
	  };
	  return *accessor(it).container;
	}
	
	template <typename T, typename Char = char, typename Enable = void>
	struct fallback_formatter {
	  fallback_formatter() = delete;
	};
	
	// Specifies if T has an enabled fallback_formatter specialization.
	template <typename T, typename Context>
	using has_fallback_formatter =
	    std::is_constructible<fallback_formatter<T, typename Context::char_type>>;
	
	template <typename Char> struct named_arg_base;
	template <typename T, typename Char> struct named_arg;
	
	enum type {
	  none_type,
	  named_arg_type,
	  // Integer types should go first,
	  int_type,
	  uint_type,
	  long_long_type,
	  ulong_long_type,
	  int128_type,
	  uint128_type,
	  bool_type,
	  char_type,
	  last_integer_type = char_type,
	  // followed by floating-point types.
	  float_type,
	  double_type,
	  long_double_type,
	  last_numeric_type = long_double_type,
	  cstring_type,
	  string_type,
	  pointer_type,
	  custom_type
	};
	
	// Maps core type T to the corresponding type enum constant.
	template <typename T, typename Char>
	struct type_constant : std::integral_constant<type, custom_type> {};
	
	#define FMT_TYPE_CONSTANT(Type, constant) \
	  template <typename Char>                \
	  struct type_constant<Type, Char> : std::integral_constant<type, constant> {}
	
	FMT_TYPE_CONSTANT(const named_arg_base<Char>&, named_arg_type);
	FMT_TYPE_CONSTANT(int, int_type);
	FMT_TYPE_CONSTANT(unsigned, uint_type);
	FMT_TYPE_CONSTANT(long long, long_long_type);
	FMT_TYPE_CONSTANT(unsigned long long, ulong_long_type);
	FMT_TYPE_CONSTANT(int128_t, int128_type);
	FMT_TYPE_CONSTANT(uint128_t, uint128_type);
	FMT_TYPE_CONSTANT(bool, bool_type);
	FMT_TYPE_CONSTANT(Char, char_type);
	FMT_TYPE_CONSTANT(float, float_type);
	FMT_TYPE_CONSTANT(double, double_type);
	FMT_TYPE_CONSTANT(long double, long_double_type);
	FMT_TYPE_CONSTANT(const Char*, cstring_type);
	FMT_TYPE_CONSTANT(basic_string_view<Char>, string_type);
	FMT_TYPE_CONSTANT(const void*, pointer_type);
	
	FMT_CONSTEXPR bool is_integral_type(type t) {
	  FMT_ASSERT(t != named_arg_type, "invalid argument type");
	  return t > none_type && t <= last_integer_type;
	}
	
	FMT_CONSTEXPR bool is_arithmetic_type(type t) {
	  FMT_ASSERT(t != named_arg_type, "invalid argument type");
	  return t > none_type && t <= last_numeric_type;
	}
	
	template <typename Char> struct string_value {
	  const Char* data;
	  std::size_t size;
	};
	
	template <typename Context> struct custom_value {
	  using parse_context = basic_format_parse_context<typename Context::char_type>;
	  const void* value;
	  void (*format)(const void* arg, parse_context& parse_ctx, Context& ctx);
	};
	
	// A formatting argument value.
	template <typename Context> class value {
	 public:
	  using char_type = typename Context::char_type;
	
	  union {
	    int int_value;
	    unsigned uint_value;
	    long long long_long_value;
	    unsigned long long ulong_long_value;
	    int128_t int128_value;
	    uint128_t uint128_value;
	    bool bool_value;
	    char_type char_value;
	    float float_value;
	    double double_value;
	    long double long_double_value;
	    const void* pointer;
	    string_value<char_type> string;
	    custom_value<Context> custom;
	    const named_arg_base<char_type>* named_arg;
	  };
	
	  FMT_CONSTEXPR value(int val = 0) : int_value(val) {}
	  FMT_CONSTEXPR value(unsigned val) : uint_value(val) {}
	  value(long long val) : long_long_value(val) {}
	  value(unsigned long long val) : ulong_long_value(val) {}
	  value(int128_t val) : int128_value(val) {}
	  value(uint128_t val) : uint128_value(val) {}
	  value(float val) : float_value(val) {}
	  value(double val) : double_value(val) {}
	  value(long double val) : long_double_value(val) {}
	  value(bool val) : bool_value(val) {}
	  value(char_type val) : char_value(val) {}
	  value(const char_type* val) { string.data = val; }
	  value(basic_string_view<char_type> val) {
	    string.data = val.data();
	    string.size = val.size();
	  }
	  value(const void* val) : pointer(val) {}
	
	  template <typename T> value(const T& val) {
	    custom.value = &val;
	    // Get the formatter type through the context to allow different contexts
	    // have different extension points, e.g. `formatter<T>` for `format` and
	    // `printf_formatter<T>` for `printf`.
	    custom.format = format_custom_arg<
	        T, conditional_t<has_formatter<T, Context>::value,
	                         typename Context::template formatter_type<T>,
	                         fallback_formatter<T, char_type>>>;
	  }
	
	  value(const named_arg_base<char_type>& val) { named_arg = &val; }
	
	 private:
	  // Formats an argument of a custom type, such as a user-defined class.
	  template <typename T, typename Formatter>
	  static void format_custom_arg(
	      const void* arg, basic_format_parse_context<char_type>& parse_ctx,
	      Context& ctx) {
	    Formatter f;
	    parse_ctx.advance_to(f.parse(parse_ctx));
	    ctx.advance_to(f.format(*static_cast<const T*>(arg), ctx));
	  }
	};
	
	template <typename Context, typename T>
	FMT_CONSTEXPR basic_format_arg<Context> make_arg(const T& value);
	
	// To minimize the number of types we need to deal with, long is translated
	// either to int or to long long depending on its size.
	enum { long_short = sizeof(long) == sizeof(int) };
	using long_type = conditional_t<long_short, int, long long>;
	using ulong_type = conditional_t<long_short, unsigned, unsigned long long>;
	
	// Maps formatting arguments to core types.
	template <typename Context> struct arg_mapper {
	  using char_type = typename Context::char_type;
	
	  FMT_CONSTEXPR int map(signed char val) { return val; }
	  FMT_CONSTEXPR unsigned map(unsigned char val) { return val; }
	  FMT_CONSTEXPR int map(short val) { return val; }
	  FMT_CONSTEXPR unsigned map(unsigned short val) { return val; }
	  FMT_CONSTEXPR int map(int val) { return val; }
	  FMT_CONSTEXPR unsigned map(unsigned val) { return val; }
	  FMT_CONSTEXPR long_type map(long val) { return val; }
	  FMT_CONSTEXPR ulong_type map(unsigned long val) { return val; }
	  FMT_CONSTEXPR long long map(long long val) { return val; }
	  FMT_CONSTEXPR unsigned long long map(unsigned long long val) { return val; }
	  FMT_CONSTEXPR int128_t map(int128_t val) { return val; }
	  FMT_CONSTEXPR uint128_t map(uint128_t val) { return val; }
	  FMT_CONSTEXPR bool map(bool val) { return val; }
	
	  template <typename T, FMT_ENABLE_IF(is_char<T>::value)>
	  FMT_CONSTEXPR char_type map(T val) {
	    static_assert(
	        std::is_same<T, char>::value || std::is_same<T, char_type>::value,
	        "mixing character types is disallowed");
	    return val;
	  }
	
	  FMT_CONSTEXPR float map(float val) { return val; }
	  FMT_CONSTEXPR double map(double val) { return val; }
	  FMT_CONSTEXPR long double map(long double val) { return val; }
	
	  FMT_CONSTEXPR const char_type* map(char_type* val) { return val; }
	  FMT_CONSTEXPR const char_type* map(const char_type* val) { return val; }
	  template <typename T, FMT_ENABLE_IF(is_string<T>::value)>
	  FMT_CONSTEXPR basic_string_view<char_type> map(const T& val) {
	    static_assert(std::is_same<char_type, char_t<T>>::value,
	                  "mixing character types is disallowed");
	    return to_string_view(val);
	  }
	  template <typename T,
	            FMT_ENABLE_IF(
	                std::is_constructible<basic_string_view<char_type>, T>::value &&
	                !is_string<T>::value)>
	  FMT_CONSTEXPR basic_string_view<char_type> map(const T& val) {
	    return basic_string_view<char_type>(val);
	  }
	  template <
	      typename T,
	      FMT_ENABLE_IF(
	          std::is_constructible<std_string_view<char_type>, T>::value &&
	          !std::is_constructible<basic_string_view<char_type>, T>::value &&
	          !is_string<T>::value && !has_formatter<T, Context>::value)>
	  FMT_CONSTEXPR basic_string_view<char_type> map(const T& val) {
	    return std_string_view<char_type>(val);
	  }
	  FMT_CONSTEXPR const char* map(const signed char* val) {
	    static_assert(std::is_same<char_type, char>::value, "invalid string type");
	    return reinterpret_cast<const char*>(val);
	  }
	  FMT_CONSTEXPR const char* map(const unsigned char* val) {
	    static_assert(std::is_same<char_type, char>::value, "invalid string type");
	    return reinterpret_cast<const char*>(val);
	  }
	
	  FMT_CONSTEXPR const void* map(void* val) { return val; }
	  FMT_CONSTEXPR const void* map(const void* val) { return val; }
	  FMT_CONSTEXPR const void* map(std::nullptr_t val) { return val; }
	  template <typename T> FMT_CONSTEXPR int map(const T*) {
	    // Formatting of arbitrary pointers is disallowed. If you want to output
	    // a pointer cast it to "void *" or "const void *". In particular, this
	    // forbids formatting of "[const] volatile char *" which is printed as bool
	    // by iostreams.
	    static_assert(!sizeof(T), "formatting of non-void pointers is disallowed");
	    return 0;
	  }
	
	  template <typename T,
	            FMT_ENABLE_IF(std::is_enum<T>::value &&
	                          !has_formatter<T, Context>::value &&
	                          !has_fallback_formatter<T, Context>::value)>
	  FMT_CONSTEXPR auto map(const T& val) -> decltype(
	      map(static_cast<typename std::underlying_type<T>::type>(val))) {
	    return map(static_cast<typename std::underlying_type<T>::type>(val));
	  }
	  template <
	      typename T,
	      FMT_ENABLE_IF(
	          !is_string<T>::value && !is_char<T>::value &&
	          !std::is_constructible<basic_string_view<char_type>, T>::value &&
	          (has_formatter<T, Context>::value ||
	           (has_fallback_formatter<T, Context>::value &&
	            !std::is_constructible<std_string_view<char_type>, T>::value)))>
	  FMT_CONSTEXPR const T& map(const T& val) {
	    return val;
	  }
	
	  template <typename T>
	  FMT_CONSTEXPR const named_arg_base<char_type>& map(
	      const named_arg<T, char_type>& val) {
	    auto arg = make_arg<Context>(val.value);
	    std::memcpy(val.data, &arg, sizeof(arg));
	    return val;
	  }
	};
	
	// A type constant after applying arg_mapper<Context>.
	template <typename T, typename Context>
	using mapped_type_constant =
	    type_constant<decltype(arg_mapper<Context>().map(std::declval<const T&>())),
	                  typename Context::char_type>;
	
	enum { packed_arg_bits = 5 };
	// Maximum number of arguments with packed types.
	enum { max_packed_args = 63 / packed_arg_bits };
	enum : unsigned long long { is_unpacked_bit = 1ULL << 63 };
	
	template <typename Context> class arg_map;
	}  // namespace internal
	
	// A formatting argument. It is a trivially copyable/constructible type to
	// allow storage in basic_memory_buffer.
	template <typename Context> class basic_format_arg {
	 private:
	  internal::value<Context> value_;
	  internal::type type_;
	
	  template <typename ContextType, typename T>
	  friend FMT_CONSTEXPR basic_format_arg<ContextType> internal::make_arg(
	      const T& value);
	
	  template <typename Visitor, typename Ctx>
	  friend FMT_CONSTEXPR auto visit_format_arg(Visitor&& vis,
	                                             const basic_format_arg<Ctx>& arg)
	      -> decltype(vis(0));
	
	  friend class basic_format_args<Context>;
	  friend class internal::arg_map<Context>;
	
	  using char_type = typename Context::char_type;
	
	 public:
	  class handle {
	   public:
	    explicit handle(internal::custom_value<Context> custom) : custom_(custom) {}
	
	    void format(basic_format_parse_context<char_type>& parse_ctx,
	                Context& ctx) const {
	      custom_.format(custom_.value, parse_ctx, ctx);
	    }
	
	   private:
	    internal::custom_value<Context> custom_;
	  };
	
	  FMT_CONSTEXPR basic_format_arg() : type_(internal::none_type) {}
	
	  FMT_CONSTEXPR explicit operator bool() const FMT_NOEXCEPT {
	    return type_ != internal::none_type;
	  }
	
	  internal::type type() const { return type_; }
	
	  bool is_integral() const { return internal::is_integral_type(type_); }
	  bool is_arithmetic() const { return internal::is_arithmetic_type(type_); }
	};
	
	/**
	  \rst
	  Visits an argument dispatching to the appropriate visit method based on
	  the argument type. For example, if the argument type is ``double`` then
	  ``vis(value)`` will be called with the value of type ``double``.
	  \endrst
	 */
	template <typename Visitor, typename Context>
	FMT_CONSTEXPR auto visit_format_arg(Visitor&& vis,
	                                    const basic_format_arg<Context>& arg)
	    -> decltype(vis(0)) {
	  using char_type = typename Context::char_type;
	  switch (arg.type_) {
	  case internal::none_type:
	    break;
	  case internal::named_arg_type:
	    FMT_ASSERT(false, "invalid argument type");
	    break;
	  case internal::int_type:
	    return vis(arg.value_.int_value);
	  case internal::uint_type:
	    return vis(arg.value_.uint_value);
	  case internal::long_long_type:
	    return vis(arg.value_.long_long_value);
	  case internal::ulong_long_type:
	    return vis(arg.value_.ulong_long_value);
	#if FMT_USE_INT128
	  case internal::int128_type:
	    return vis(arg.value_.int128_value);
	  case internal::uint128_type:
	    return vis(arg.value_.uint128_value);
	#else
	  case internal::int128_type:
	  case internal::uint128_type:
	    break;
	#endif
	  case internal::bool_type:
	    return vis(arg.value_.bool_value);
	  case internal::char_type:
	    return vis(arg.value_.char_value);
	  case internal::float_type:
	    return vis(arg.value_.float_value);
	  case internal::double_type:
	    return vis(arg.value_.double_value);
	  case internal::long_double_type:
	    return vis(arg.value_.long_double_value);
	  case internal::cstring_type:
	    return vis(arg.value_.string.data);
	  case internal::string_type:
	    return vis(basic_string_view<char_type>(arg.value_.string.data,
	                                            arg.value_.string.size));
	  case internal::pointer_type:
	    return vis(arg.value_.pointer);
	  case internal::custom_type:
	    return vis(typename basic_format_arg<Context>::handle(arg.value_.custom));
	  }
	  return vis(monostate());
	}
	
	namespace internal {
	// A map from argument names to their values for named arguments.
	template <typename Context> class arg_map {
	 private:
	  using char_type = typename Context::char_type;
	
	  struct entry {
	    basic_string_view<char_type> name;
	    basic_format_arg<Context> arg;
	  };
	
	  entry* map_;
	  unsigned size_;
	
	  void push_back(value<Context> val) {
	    const auto& named = *val.named_arg;
	    map_[size_] = {named.name, named.template deserialize<Context>()};
	    ++size_;
	  }
	
	 public:
	  arg_map(const arg_map&) = delete;
	  void operator=(const arg_map&) = delete;
	  arg_map() : map_(nullptr), size_(0) {}
	  void init(const basic_format_args<Context>& args);
	  ~arg_map() { delete[] map_; }
	
	  basic_format_arg<Context> find(basic_string_view<char_type> name) const {
	    // The list is unsorted, so just return the first matching name.
	    for (entry *it = map_, *end = map_ + size_; it != end; ++it) {
	      if (it->name == name) return it->arg;
	    }
	    return {};
	  }
	};
	
	// A type-erased reference to an std::locale to avoid heavy <locale> include.
	class locale_ref {
	 private:
	  const void* locale_;  // A type-erased pointer to std::locale.
	
	 public:
	  locale_ref() : locale_(nullptr) {}
	  template <typename Locale> explicit locale_ref(const Locale& loc);
	
	  explicit operator bool() const FMT_NOEXCEPT { return locale_ != nullptr; }
	
	  template <typename Locale> Locale get() const;
	};
	
	template <typename> constexpr unsigned long long encode_types() { return 0; }
	
	template <typename Context, typename Arg, typename... Args>
	constexpr unsigned long long encode_types() {
	  return mapped_type_constant<Arg, Context>::value |
	         (encode_types<Context, Args...>() << packed_arg_bits);
	}
	
	template <typename Context, typename T>
	FMT_CONSTEXPR basic_format_arg<Context> make_arg(const T& value) {
	  basic_format_arg<Context> arg;
	  arg.type_ = mapped_type_constant<T, Context>::value;
	  arg.value_ = arg_mapper<Context>().map(value);
	  return arg;
	}
	
	template <bool IS_PACKED, typename Context, typename T,
	          FMT_ENABLE_IF(IS_PACKED)>
	inline value<Context> make_arg(const T& val) {
	  return arg_mapper<Context>().map(val);
	}
	
	template <bool IS_PACKED, typename Context, typename T,
	          FMT_ENABLE_IF(!IS_PACKED)>
	inline basic_format_arg<Context> make_arg(const T& value) {
	  return make_arg<Context>(value);
	}
	}  // namespace internal
	
	// Formatting context.
	template <typename OutputIt, typename Char> class basic_format_context {
	 public:
	  /** The character type for the output. */
	  using char_type = Char;
	
	 private:
	  OutputIt out_;
	  basic_format_args<basic_format_context> args_;
	  internal::arg_map<basic_format_context> map_;
	  internal::locale_ref loc_;
	
	 public:
	  using iterator = OutputIt;
	  using format_arg = basic_format_arg<basic_format_context>;
	  template <typename T> using formatter_type = formatter<T, char_type>;
	
	  basic_format_context(const basic_format_context&) = delete;
	  void operator=(const basic_format_context&) = delete;
	  /**
	   Constructs a ``basic_format_context`` object. References to the arguments are
	   stored in the object so make sure they have appropriate lifetimes.
	   */
	  basic_format_context(OutputIt out,
	                       basic_format_args<basic_format_context> ctx_args,
	                       internal::locale_ref loc = internal::locale_ref())
	      : out_(out), args_(ctx_args), loc_(loc) {}
	
	  format_arg arg(int id) const { return args_.get(id); }
	
	  // Checks if manual indexing is used and returns the argument with the
	  // specified name.
	  format_arg arg(basic_string_view<char_type> name);
	
	  internal::error_handler error_handler() { return {}; }
	  void on_error(const char* message) { error_handler().on_error(message); }
	
	  // Returns an iterator to the beginning of the output range.
	  iterator out() { return out_; }
	
	  // Advances the begin iterator to ``it``.
	  void advance_to(iterator it) { out_ = it; }
	
	  internal::locale_ref locale() { return loc_; }
	};
	
	template <typename Char>
	using buffer_context =
	    basic_format_context<std::back_insert_iterator<internal::buffer<Char>>,
	                         Char>;
	using format_context = buffer_context<char>;
	using wformat_context = buffer_context<wchar_t>;
	
	/**
	  \rst
	  An array of references to arguments. It can be implicitly converted into
	  `~fmt::basic_format_args` for passing into type-erased formatting functions
	  such as `~fmt::vformat`.
	  \endrst
	 */
	template <typename Context, typename... Args> class format_arg_store {
	 private:
	  static const size_t num_args = sizeof...(Args);
	  static const bool is_packed = num_args < internal::max_packed_args;
	
	  using value_type = conditional_t<is_packed, internal::value<Context>,
	                                   basic_format_arg<Context>>;
	
	  // If the arguments are not packed, add one more element to mark the end.
	  value_type data_[num_args + (num_args == 0 ? 1 : 0)];
	
	  friend class basic_format_args<Context>;
	
	 public:
	  static constexpr unsigned long long types =
	      is_packed ? internal::encode_types<Context, Args...>()
	                : internal::is_unpacked_bit | num_args;
	
	  format_arg_store(const Args&... args)
	      : data_{internal::make_arg<is_packed, Context>(args)...} {}
	};
	
	/**
	  \rst
	  Constructs an `~fmt::format_arg_store` object that contains references to
	  arguments and can be implicitly converted to `~fmt::format_args`. `Context`
	  can be omitted in which case it defaults to `~fmt::context`.
	  See `~fmt::arg` for lifetime considerations.
	  \endrst
	 */
	template <typename Context = format_context, typename... Args>
	inline format_arg_store<Context, Args...> make_format_args(
	    const Args&... args) {
	  return {args...};
	}
	
	/** Formatting arguments. */
	template <typename Context> class basic_format_args {
	 public:
	  using size_type = int;
	  using format_arg = basic_format_arg<Context>;
	
	 private:
	  // To reduce compiled code size per formatting function call, types of first
	  // max_packed_args arguments are passed in the types_ field.
	  unsigned long long types_;
	  union {
	    // If the number of arguments is less than max_packed_args, the argument
	    // values are stored in values_, otherwise they are stored in args_.
	    // This is done to reduce compiled code size as storing larger objects
	    // may require more code (at least on x86-64) even if the same amount of
	    // data is actually copied to stack. It saves ~10% on the bloat test.
	    const internal::value<Context>* values_;
	    const format_arg* args_;
	  };
	
	  bool is_packed() const { return (types_ & internal::is_unpacked_bit) == 0; }
	
	  internal::type type(int index) const {
	    int shift = index * internal::packed_arg_bits;
	    unsigned int mask = (1 << internal::packed_arg_bits) - 1;
	    return static_cast<internal::type>((types_ >> shift) & mask);
	  }
	
	  friend class internal::arg_map<Context>;
	
	  void set_data(const internal::value<Context>* values) { values_ = values; }
	  void set_data(const format_arg* args) { args_ = args; }
	
	  format_arg do_get(int index) const {
	    format_arg arg;
	    if (!is_packed()) {
	      auto num_args = max_size();
	      if (index < num_args) arg = args_[index];
	      return arg;
	    }
	    if (index > internal::max_packed_args) return arg;
	    arg.type_ = type(index);
	    if (arg.type_ == internal::none_type) return arg;
	    internal::value<Context>& val = arg.value_;
	    val = values_[index];
	    return arg;
	  }
	
	 public:
	  basic_format_args() : types_(0) {}
	
	  /**
	   \rst
	   Constructs a `basic_format_args` object from `~fmt::format_arg_store`.
	   \endrst
	   */
	  template <typename... Args>
	  basic_format_args(const format_arg_store<Context, Args...>& store)
	      : types_(store.types) {
	    set_data(store.data_);
	  }
	
	  /**
	   \rst
	   Constructs a `basic_format_args` object from a dynamic set of arguments.
	   \endrst
	   */
	  basic_format_args(const format_arg* args, int count)
	      : types_(internal::is_unpacked_bit | internal::to_unsigned(count)) {
	    set_data(args);
	  }
	
	  /** Returns the argument at specified index. */
	  format_arg get(int index) const {
	    format_arg arg = do_get(index);
	    if (arg.type_ == internal::named_arg_type)
	      arg = arg.value_.named_arg->template deserialize<Context>();
	    return arg;
	  }
	
	  int max_size() const {
	    unsigned long long max_packed = internal::max_packed_args;
	    return static_cast<int>(is_packed() ? max_packed
	                                        : types_ & ~internal::is_unpacked_bit);
	  }
	};
	
	/** An alias to ``basic_format_args<context>``. */
	// It is a separate type rather than an alias to make symbols readable.
	struct format_args : basic_format_args<format_context> {
	  template <typename... Args>
	  format_args(Args&&... args)
	      : basic_format_args<format_context>(std::forward<Args>(args)...) {}
	};
	struct wformat_args : basic_format_args<wformat_context> {
	  template <typename... Args>
	  wformat_args(Args&&... args)
	      : basic_format_args<wformat_context>(std::forward<Args>(args)...) {}
	};
	
	template <typename Container> struct is_contiguous : std::false_type {};
	
	template <typename Char>
	struct is_contiguous<std::basic_string<Char>> : std::true_type {};
	
	template <typename Char>
	struct is_contiguous<internal::buffer<Char>> : std::true_type {};
	
	namespace internal {
	
	template <typename OutputIt>
	struct is_contiguous_back_insert_iterator : std::false_type {};
	template <typename Container>
	struct is_contiguous_back_insert_iterator<std::back_insert_iterator<Container>>
	    : is_contiguous<Container> {};
	
	template <typename Char> struct named_arg_base {
	  basic_string_view<Char> name;
	
	  // Serialized value<context>.
	  mutable char data[sizeof(basic_format_arg<buffer_context<Char>>)];
	
	  named_arg_base(basic_string_view<Char> nm) : name(nm) {}
	
	  template <typename Context> basic_format_arg<Context> deserialize() const {
	    basic_format_arg<Context> arg;
	    std::memcpy(&arg, data, sizeof(basic_format_arg<Context>));
	    return arg;
	  }
	};
	
	template <typename T, typename Char> struct named_arg : named_arg_base<Char> {
	  const T& value;
	
	  named_arg(basic_string_view<Char> name, const T& val)
	      : named_arg_base<Char>(name), value(val) {}
	};
	
	template <typename..., typename S, FMT_ENABLE_IF(!is_compile_string<S>::value)>
	inline void check_format_string(const S&) {
	#if defined(FMT_ENFORCE_COMPILE_STRING)
	  static_assert(is_compile_string<S>::value,
	                "FMT_ENFORCE_COMPILE_STRING requires all format strings to "
	                "utilize FMT_STRING() or fmt().");
	#endif
	}
	template <typename..., typename S, FMT_ENABLE_IF(is_compile_string<S>::value)>
	void check_format_string(S);
	
	struct view {};
	template <bool...> struct bool_pack;
	template <bool... Args>
	using all_true =
	    std::is_same<bool_pack<Args..., true>, bool_pack<true, Args...>>;
	
	template <typename... Args, typename S, typename Char = char_t<S>>
	inline format_arg_store<buffer_context<Char>, remove_reference_t<Args>...>
	make_args_checked(const S& format_str,
	                  const remove_reference_t<Args>&... args) {
	  static_assert(all_true<(!std::is_base_of<view, remove_reference_t<Args>>() ||
	                          !std::is_reference<Args>())...>::value,
	                "passing views as lvalues is disallowed");
	  check_format_string<remove_const_t<remove_reference_t<Args>>...>(format_str);
	  return {args...};
	}
	
	template <typename Char>
	std::basic_string<Char> vformat(basic_string_view<Char> format_str,
	                                basic_format_args<buffer_context<Char>> args);
	
	template <typename Char>
	typename buffer_context<Char>::iterator vformat_to(
	    buffer<Char>& buf, basic_string_view<Char> format_str,
	    basic_format_args<buffer_context<Char>> args);
	}  // namespace internal
	
	/**
	  \rst
	  Returns a named argument to be used in a formatting function.
	
	  The named argument holds a reference and does not extend the lifetime
	  of its arguments.
	  Consequently, a dangling reference can accidentally be created.
	  The user should take care to only pass this function temporaries when
	  the named argument is itself a temporary, as per the following example.
	
	  **Example**::
	
	    fmt::print("Elapsed time: {s:.2f} seconds", fmt::arg("s", 1.23));
	  \endrst
	 */
	template <typename S, typename T, typename Char = char_t<S>>
	inline internal::named_arg<T, Char> arg(const S& name, const T& arg) {
	  static_assert(internal::is_string<S>::value, "");
	  return {name, arg};
	}
	
	// Disable nested named arguments, e.g. ``arg("a", arg("b", 42))``.
	template <typename S, typename T, typename Char>
	void arg(S, internal::named_arg<T, Char>) = delete;
	
	/** Formats a string and writes the output to ``out``. */
	// GCC 8 and earlier cannot handle std::back_insert_iterator<Container> with
	// vformat_to<ArgFormatter>(...) overload, so SFINAE on iterator type instead.
	template <typename OutputIt, typename S, typename Char = char_t<S>,
	          FMT_ENABLE_IF(
	              internal::is_contiguous_back_insert_iterator<OutputIt>::value)>
	OutputIt vformat_to(OutputIt out, const S& format_str,
	                    basic_format_args<buffer_context<Char>> args) {
	  using container = remove_reference_t<decltype(internal::get_container(out))>;
	  internal::container_buffer<container> buf((internal::get_container(out)));
	  internal::vformat_to(buf, to_string_view(format_str), args);
	  return out;
	}
	
	template <typename Container, typename S, typename... Args,
	          FMT_ENABLE_IF(
	              is_contiguous<Container>::value&& internal::is_string<S>::value)>
	inline std::back_insert_iterator<Container> format_to(
	    std::back_insert_iterator<Container> out, const S& format_str,
	    Args&&... args) {
	  return vformat_to(
	      out, to_string_view(format_str),
	      {internal::make_args_checked<Args...>(format_str, args...)});
	}
	
	template <typename S, typename Char = char_t<S>>
	inline std::basic_string<Char> vformat(
	    const S& format_str, basic_format_args<buffer_context<Char>> args) {
	  return internal::vformat(to_string_view(format_str), args);
	}
	
	/**
	  \rst
	  Formats arguments and returns the result as a string.
	
	  **Example**::
	
	    #include <fmt/core.h>
	    std::string message = fmt::format("The answer is {}", 42);
	  \endrst
	*/
	// Pass char_t as a default template parameter instead of using
	// std::basic_string<char_t<S>> to reduce the symbol size.
	template <typename S, typename... Args, typename Char = char_t<S>>
	inline std::basic_string<Char> format(const S& format_str, Args&&... args) {
	  return internal::vformat(
	      to_string_view(format_str),
	      {internal::make_args_checked<Args...>(format_str, args...)});
	}
	
	FMT_API void vprint(std::FILE* f, string_view format_str, format_args args);
	FMT_API void vprint(string_view format_str, format_args args);
	
	/**
	  \rst
	  Prints formatted data to the file *f*. For wide format strings,
	  *f* should be in wide-oriented mode set via ``fwide(f, 1)`` or
	  ``_setmode(_fileno(f), _O_U8TEXT)`` on Windows.
	
	  **Example**::
	
	    fmt::print(stderr, "Don't {}!", "panic");
	  \endrst
	 */
	template <typename S, typename... Args,
	          FMT_ENABLE_IF(internal::is_string<S>::value)>
	inline void print(std::FILE* f, const S& format_str, Args&&... args) {
	  vprint(f, to_string_view(format_str),
	         internal::make_args_checked<Args...>(format_str, args...));
	}
	
	/**
	  \rst
	  Prints formatted data to ``stdout``.
	
	  **Example**::
	
	    fmt::print("Elapsed time: {0:.2f} seconds", 1.23);
	  \endrst
	 */
	template <typename S, typename... Args,
	          FMT_ENABLE_IF(internal::is_string<S>::value)>
	inline void print(const S& format_str, Args&&... args) {
	  vprint(to_string_view(format_str),
	         internal::make_args_checked<Args...>(format_str, args...));
	}
	FMT_END_NAMESPACE
	
	#endif  // FMT_CORE_H_