Contexts and scanners module

Scanning user-defined types

User-defined types can be scanned by specializing the class template scn::scanner.

struct mytype {
  int key;
  std::string value;
};

template <>
struct scn::scanner<mytype> {
  template <typename ParseContext>
  constexpr auto parse(ParseCtx& pctx)
    -> scan_expected<typename ParseContext::iterator> {
    // parse() implementation just returning begin():
    // only permits empty format specifiers
    return pctx.begin();
  }

  template <typename Context>
  auto scan(mytype& val, Context& ctx)
    -> scan_expected<typename Context::iterator> {
    return scn::scan<int, std::string>(ctx.range(), "{}: {}")
      .transform([&](auto result) {
        std::tie(val.key, val.value) = std::move(result->values());
        return result.begin();
      });
  }
};

See also User types

Classes

template <typename CharT>

class scn::basic_scan_context

template <typename CharT>

class scn::basic_scan_parse_context

template <typename T, typename CharT = char, typename Enable = void>

struct scn::scanner

template <typename T, typename CharT>

struct scn::scanner<T, CharT, std::enable_if_t<detail::arg_type_constant<T, CharT>::value !=detail::arg_type::custom_type && !detail::is_type_disabled<T>>>