Function parse_replacement_field

include/fmt/base.h:1582–1626

template <typename Char, typename Handler>
FMT_CONSTEXPR FMT_INLINE auto parse_replacement_field(const Char* begin,
                                                      const Char* end,
                                                      Handler&& handler)
    -> const Char* {
  ++begin;
  if (begin == end) {
    handler.on_error("invalid format string");
    return end;
  }
  int arg_id = 0;
  switch (*begin) {
  case '}':
    handler.on_replacement_field(handler.on_arg_id(), begin);
    return begin + 1;
  case '{': handler.on_text(begin, begin + 1); return begin + 1;
  case ':': arg_id = handler.on_arg_id(); break;
  default:  {
    struct id_adapter {
      Handler& handler;
      int arg_id;

      FMT_CONSTEXPR void on_index(int id) { arg_id = handler.on_arg_id(id); }
      FMT_CONSTEXPR void on_name(basic_string_view<Char> id) {
        arg_id = handler.on_arg_id(id);
      }
    } adapter = {handler, 0};
    begin = parse_arg_id(begin, end, adapter);
    arg_id = adapter.arg_id;
    Char c = begin != end ? *begin : Char();
    if (c == '}') {
      handler.on_replacement_field(arg_id, begin);
      return begin + 1;
    }
    if (c != ':') {
      handler.on_error("missing '}' in format string");
      return end;
    }
    break;
  }
  }
  begin = handler.on_format_specs(arg_id, begin + 1, end);
  if (begin == end || *begin != '}')
    return handler.on_error("unknown format specifier"), end;
  return begin + 1;
}

template <typename Char, typename Handler>
FMT_CONSTEXPR void parse_format_string(basic_string_view<Char> fmt,