//******************************************************** // The following code example is taken from the book // C++20 - The Complete Guide // by Nicolai M. Josuttis (www.josuttis.com) // http://www.cppstd20.com // // The code is licensed under a // Creative Commons Attribution 4.0 International License // http://creativecommons.org/licenses/by/4.0/ //******************************************************** #include "always42.hpp" #include //*** formatter for type Always42: template<> struct std::formatter { // use a standard int formatter that does the work: #if __cpp_lib_format < 202106 mutable // in case the standard formatters have a non-const format() #endif std::formatter f; // delegate parsing to the standard int formatter: #if __cpp_lib_format >= 202106 constexpr // in case standard formatters don't support constexpr parse() yet #endif auto parse(std::format_parse_context& ctx) { return f.parse(ctx); } // delegate formatting of the int value to the standard int formatter: auto format(const Always42& obj, std::format_context& ctx) const { return f.format(obj.getValue(), ctx); } };