Function parse

include/fmt/ranges.h:431–469

  }

  FMT_CONSTEXPR auto parse(parse_context<Char>& ctx) -> const Char* {
    auto it = ctx.begin();
    auto end = ctx.end();
    detail::maybe_set_debug_format(underlying_, true);
    if (it == end) return underlying_.parse(ctx);

    switch (detail::to_ascii(*it)) {
    case 'n':
      set_brackets({}, {});
      ++it;
      break;
    case '?':
      is_debug = true;
      set_brackets({}, {});
      ++it;
      if (it == end || *it != 's') report_error("invalid format specifier");
      FMT_FALLTHROUGH;
    case 's':
      if (!std::is_same<T, Char>::value)
        report_error("invalid format specifier");
      if (!is_debug) {
        set_brackets(detail::string_literal<Char, '"'>{},
                     detail::string_literal<Char, '"'>{});
        set_separator({});
        detail::maybe_set_debug_format(underlying_, false);
      }
      ++it;
      return it;
    }

    if (it != end && *it != '}') {
      if (*it != ':') report_error("invalid format specifier");
      detail::maybe_set_debug_format(underlying_, false);
      ++it;
    }

    ctx.advance_to(it);
    return underlying_.parse(ctx);
  }

  template <typename R, typename FormatContext>
  FMT_CONSTEXPR auto format(R&& range, FormatContext& ctx) const