Magic enum format in a separated header file (#185)

include/magic_enum_format.hpp

@@ -0,0 +1,79 @@
+//  __  __             _        ______                          _____
+// |  \/  |           (_)      |  ____|                        / ____|_     _
+// | \  / | __ _  __ _ _  ___  | |__   _ __  _   _ _ __ ___   | |   _| |_ _| |_
+// | |\/| |/ _` |/ _` | |/ __| |  __| | '_ \| | | | '_ ` _ \  | |  |_   _|_   _|
+// | |  | | (_| | (_| | | (__  | |____| | | | |_| | | | | | | | |____|_|   |_|
+// |_|  |_|\__,_|\__, |_|\___| |______|_| |_|\__,_|_| |_| |_|  \_____|
+//                __/ | https://github.com/Neargye/magic_enum
+//               |___/  version 0.8.0
+//
+// Licensed under the MIT License <http://opensource.org/licenses/MIT>.
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2019 - 2022 Daniil Goncharov <neargye@gmail.com>.
+//
+// Permission is hereby  granted, free of charge, to any  person obtaining a copy
+// of this software and associated  documentation files (the "Software"), to deal
+// in the Software  without restriction, including without  limitation the rights
+// to  use, copy,  modify, merge,  publish, distribute,  sublicense, and/or  sell
+// copies  of  the Software,  and  to  permit persons  to  whom  the Software  is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE  IS PROVIDED "AS  IS", WITHOUT WARRANTY  OF ANY KIND,  EXPRESS OR
+// IMPLIED,  INCLUDING BUT  NOT  LIMITED TO  THE  WARRANTIES OF  MERCHANTABILITY,
+// FITNESS FOR  A PARTICULAR PURPOSE AND  NONINFRINGEMENT. IN NO EVENT  SHALL THE
+// AUTHORS  OR COPYRIGHT  HOLDERS  BE  LIABLE FOR  ANY  CLAIM,  DAMAGES OR  OTHER
+// LIABILITY, WHETHER IN AN ACTION OF  CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE  OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+#ifndef NEARGYE_MAGIC_ENUM_FORMAT_HPP
+#define NEARGYE_MAGIC_ENUM_FORMAT_HPP
+
+#ifndef __cpp_lib_format
+#  error "Format is not supported"
+#endif
+
+#include "magic_enum.hpp"
+
+#ifndef MAGIC_ENUM_DEFAULT_ENABLE_ENUM_FORMAT
+#  define MAGIC_ENUM_DEFAULT_ENABLE_ENUM_FORMAT true
+#  define MAGIC_ENUM_DEFAULT_ENABLE_ENUM_FORMAT_AUTO_DEFINE
+#endif // MAGIC_ENUM_DEFAULT_ENABLE_ENUM_FORMAT
+
+namespace magic_enum::customize {
+  // customize enum to enable/disable automatic std::format 
+  template <typename E>
+  constexpr bool enum_format_enabled() noexcept {
+    return MAGIC_ENUM_DEFAULT_ENABLE_ENUM_FORMAT;
+  }
+} // magic_enum::customize
+
+#include <format>
+
+template<typename E>
+struct std::formatter<E, std::enable_if_t<std::is_enum_v<E> && magic_enum::customize::enum_format_enabled<E>(), char>> : std::formatter<std::string_view, char> {
+  auto format(E e, format_context& ctx) {
+    if constexpr (magic_enum::detail::is_flags_v<E>) {
+      if (auto name = magic_enum::enum_flags_name(e); !name.empty()) {
+        return this->std::formatter<std::string_view, char>::format(std::string_view{name.data(), name.size()}, ctx);
+      }
+    } else {
+      if (auto name = magic_enum::enum_name(e); !name.empty()) {
+        return this->std::formatter<std::string_view, char>::format(std::string_view{name.data(), name.size()}, ctx);
+      }
+    }
+    constexpr auto type_name = magic_enum::enum_type_name<E>();
+    throw std::format_error("Type of " + std::string{type_name.data(), type_name.size()} + " enum value: " +
+                            std::to_string(magic_enum::enum_integer(e)) + " is not exists.");
+  }
+};
+
+#ifdef MAGIC_ENUM_DEFAULT_ENABLE_ENUM_FORMAT_AUTO_DEFINE
+#  undef MAGIC_ENUM_DEFAULT_ENABLE_ENUM_FORMAT
+#  undef MAGIC_ENUM_DEFAULT_ENABLE_ENUM_FORMAT_AUTO_DEFINE
+#endif // MAGIC_ENUM_DEFAULT_ENABLE_ENUM_FORMAT_AUTO_DEFINE
+
+#endif // NEARGYE_MAGIC_ENUM_FORMAT_HPP

test/test.cpp

@@ -1201,3 +1201,13 @@ TEST_CASE("multdimensional-switch-case") {
 }
 
 #endif
+
+#ifdef __cpp_lib_format
+
+#include <magic_enum_format.hpp>
+
+TEST_CASE("format-base") {
+  REQUIRE(std::format("Test-{:~^10}.", Color::RED) == "Test-~~~red~~~~.");
+}
+
+#endif

test/test_flags.cpp

@@ -822,3 +822,13 @@ TEST_CASE("constexpr_for") {
 }
 
 #endif
+
+#ifdef __cpp_lib_format
+
+#include <magic_enum_format.hpp>
+
+TEST_CASE("format-base") {
+  REQUIRE(std::format("Test-{:~^11}.", Color::RED | Color::GREEN) == "Test-~RED|GREEN~.");
+}
+
+#endif