feat: std::format support for dpp::snowflake

CMakeLists.txt

@@ -115,3 +115,48 @@ else()
 	# that made no sense, it seems they may have changed their parsing rules somehow.
 	message("-- Using bundled nlohmann::json")
 endif()
+
+
+if(CMAKE_CXX_STANDARD GREATER_EQUAL 20 OR DPP_CORO)
+	include(CheckCXXSourceCompiles)
+	unset(HAS_FORMAT CACHE)
+	set(temp_flags "${CMAKE_REQUIRED_FLAGS}")
+	if (MSVC)
+		set(CMAKE_REQUIRED_FLAGS "/std:c++20")
+	else ()
+		set(CMAKE_REQUIRED_FLAGS "-std=c++20")
+	endif ()
+	check_cxx_source_compiles(
+		"
+		#include <format>
+		#include <string>
+
+		struct MyType {
+		int value;
+		std::string str() const { return std::to_string(value); }
+		};
+
+		template <>
+		struct std::formatter<MyType> : std::formatter<std::string> {
+		auto format(const MyType& item, std::format_context& ctx) const -> decltype(ctx.out()) {
+		  return std::format_to(ctx.out(), \"{}\", item.str());
+		}
+		};
+
+		int main() {
+		MyType my{42};
+		auto s = std::format(\"{}\", my);
+		return 0;
+		}
+		"
+		HAS_FORMAT
+
+	)
+	set(CMAKE_REQUIRED_FLAGS ${temp_flags})
+	if(HAS_FORMAT)
+		message("-- INFO: Found std::format support")
+		target_compile_definitions(dpp PUBLIC DPP_HAS_FORMAT)
+	else ()
+		message("-- INFO: std::format support not found")
+	endif()
+endif ()

include/dpp/snowflake.h

@@ -26,6 +26,11 @@
 #include <cstdint>
 #include <type_traits>
 
+#ifdef DPP_HAS_FORMAT
+#include <format>
+#endif
+
+
 /**
  * @brief The main namespace for D++ functions. classes and types
  */
@@ -281,3 +286,23 @@ struct std::hash<dpp::snowflake>
 		return std::hash<uint64_t>{}(s.value);
 	}
 };
+
+#ifdef DPP_HAS_FORMAT
+/*
+ * @brief implementation of formater for dpp::snowflake for std::format support
+ * https://en.cppreference.com/w/cpp/utility/format/formatter
+ */
+template <>
+struct std::formatter<dpp::snowflake>
+{
+        template<class TP>
+        constexpr typename TP::iterator parse(TP& ctx) {
+                return ctx.begin();
+        }
+
+        template<class TF>
+        typename TF::iterator format(const dpp::snowflake& snowflake, TF& ctx) const {
+                return std::format_to(ctx.out(), "{}", snowflake.str());
+        }
+};
+#endif //DPP_HAS_FORMAT

src/unittest/test.cpp

@@ -379,6 +379,19 @@ Markdown lol \\|\\|spoiler\\|\\| \\~\\~strikethrough\\~\\~ \\`small \\*code\\* b
 		set_test(SNOWFLAKE, success);
 	}
 
+        { // test snowflake: std::format support
+
+                #ifdef DPP_HAS_FORMAT
+                        set_test(SNOWFLAKE_STD_FORMAT,
+                            std::format("{}",dpp::snowflake{}) == "0" &&
+                            std::format("{}",dpp::snowflake{12345}) == "12345" &&
+                            std::format("{} hello {}", dpp::snowflake{12345}, dpp::snowflake{54321}) == "12345 hello 54321"
+                        );
+                #else
+                        set_status(SNOWFLAKE_STD_FORMAT,ts_skipped);
+                #endif // DPP_HAS_FORMAT
+        };
+
 	{ // test dpp::json_interface
 		start_test(JSON_INTERFACE);
 		struct fillable : dpp::json_interface<fillable> {
@@ -776,7 +789,7 @@ Markdown lol \\|\\|spoiler\\|\\| \\~\\~strikethrough\\~\\~ \\`small \\*code\\* b
 				 m5.get_url() == "" &&
 				 m6.get_url() == "" &&
 				 m7.get_url() == "" &&
-				 m8.get_url() == "" 
+				 m8.get_url() == ""
 		);
 	}
 
@@ -886,31 +899,31 @@ Markdown lol \\|\\|spoiler\\|\\| \\~\\~strikethrough\\~\\~ \\`small \\*code\\* b
 
 		set_test(UTILITY_USER_URL, false);
 		auto user_url = dpp::utility::user_url(123);
-		set_test(UTILITY_USER_URL, 
-				 user_url == dpp::utility::url_host + "/users/123" && 
+		set_test(UTILITY_USER_URL,
+				 user_url == dpp::utility::url_host + "/users/123" &&
 				 dpp::utility::user_url(0) == ""
 		);
 
 		set_test(UTILITY_MESSAGE_URL, false);
 		auto message_url = dpp::utility::message_url(1,2,3);
 		set_test(UTILITY_MESSAGE_URL,
-				 message_url == dpp::utility::url_host+ "/channels/1/2/3" && 
+				 message_url == dpp::utility::url_host+ "/channels/1/2/3" &&
 				 dpp::utility::message_url(0,2,3) == "" &&
-				 dpp::utility::message_url(1,0,3) == "" && 
+				 dpp::utility::message_url(1,0,3) == "" &&
 				 dpp::utility::message_url(1,2,0) == "" &&
 				 dpp::utility::message_url(0,0,3) == "" &&
 				 dpp::utility::message_url(0,2,0) == "" &&
 				 dpp::utility::message_url(1,0,0) == "" &&
-				 dpp::utility::message_url(0,0,0) == "" 
+				 dpp::utility::message_url(0,0,0) == ""
 		);
 
 		set_test(UTILITY_CHANNEL_URL, false);
 		auto channel_url = dpp::utility::channel_url(1,2);
-		set_test(UTILITY_CHANNEL_URL, 
+		set_test(UTILITY_CHANNEL_URL,
 				 channel_url == dpp::utility::url_host+ "/channels/1/2" &&
 				 dpp::utility::channel_url(0,2) == "" &&
 				 dpp::utility::channel_url(1,0) == "" &&
-				 dpp::utility::channel_url(0,0) == "" 
+				 dpp::utility::channel_url(0,0) == ""
 		);
 
 		set_test(UTILITY_THREAD_URL, false);
@@ -919,7 +932,7 @@ Markdown lol \\|\\|spoiler\\|\\| \\~\\~strikethrough\\~\\~ \\`small \\*code\\* b
 				 thread_url == dpp::utility::url_host+ "/channels/1/2" &&
 				 dpp::utility::thread_url(0,2) == "" &&
 				 dpp::utility::thread_url(1,0) == "" &&
-				 dpp::utility::thread_url(0,0) == "" 
+				 dpp::utility::thread_url(0,0) == ""
 		);
 	}
 
@@ -1648,7 +1661,7 @@ Markdown lol \\|\\|spoiler\\|\\| \\~\\~strikethrough\\~\\~ \\`small \\*code\\* b
 									set_test(TIMESTAMP, false);
 								}
 							} else {
-								set_test(MESSAGESGET, false);	
+								set_test(MESSAGESGET, false);
 							}
 						}  else {
 							set_test(MESSAGESGET, false);

src/unittest/test.h

@@ -264,6 +264,8 @@ DPP_TEST(CORO_EVENT_HANDLER, "coro: online event handler", tf_online | tf_coro);
 DPP_TEST(CORO_API_CALLS, "coro: online api calls", tf_online | tf_coro);
 DPP_TEST(CORO_MUMBO_JUMBO, "coro: online mumbo jumbo in event handler", tf_online | tf_coro | tf_extended);
 
+DPP_TEST(SNOWFLAKE_STD_FORMAT, "snowflake: std::format support", tf_offline);
+
 void coro_offline_tests();
 void coro_online_tests(dpp::cluster *bot);