在现代C ++ 11 / C ++ 14 / C ++ 17和未来的C ++ 20中枚举为字符串 [英] enum to string in modern C++11 / C++14 / C++17 and future C++20
问题描述
- 2008 c 是否有一种简单的方法可以将C ++枚举转换为
- 2008 c 在C中将枚举类型的变量用作字符串的简便方法吗？
- 2008 c ++ 的问题如何轻松将c ++枚举映射到字符串
- 2008 c ++ 既使C标识符又使字符串？
- 2008 c ++ 是否有简单的脚本将C ++枚举转换为字符串？
- 2009 c ++ 如何在C ++中将枚举用作标志？
- 2011 c ++ 如何将枚举类型变量转换为
- 2011 c ++ 枚举到字符串C ++
- 2011 c ++ 如何将枚举类型变量转换为字符串？
- 2012 c 如何将枚举名称转换为c中的字符串
- 2013 c 对C中有条件编译的枚举进行字符串化
- 2008 c Is there a simple way to convert C++ enum to string?
- 2008 c Easy way to use variables of enum types as string in C?
- 2008 c++ How to easily map c++ enums to strings
- 2008 c++ Making something both a C identifier and a string?
- 2008 c++ Is there a simple script to convert C++ enum to string?
- 2009 c++ How to use enums as flags in C++?
- 2011 c++ How to convert an enum type variable to a string?
- 2011 c++ Enum to String C++
- 2011 c++ How to convert an enum type variable to a string?
- 2012 c How to convert enum names to string in c
- 2013 c Stringifying an conditionally compiled enum in C
- 使用
- 或其他可以立即使用的东西在 Boost
- 还有其他计划的< a href = https://en.wikipedia.org/wiki/C%2B%2B20 rel = noreferrer> C ++ 20
- Elegant way using C++11, C++14 or C++17 new features
- Or something ready-to-use in Boost
- Else something planned for C++20
一个示例通常比一个长的ex更好
您可以在 Coliru 上编译并运行此代码段。
（另一个以前的示例也可用）
An example is often better than a long explanation.
You can compile and run this snippet on Coliru.
(Another former example is also available)
#include <map>
#include <iostream>
struct MyClass
{
enum class MyEnum : char {
AAA = -8,
BBB = '8',
CCC = AAA + BBB
};
};
// Replace magic() by some faster compile-time generated code
// (you're allowed to replace the return type with std::string
// if that's easier for you)
const char* magic (MyClass::MyEnum e)
{
const std::map<MyClass::MyEnum,const char*> MyEnumStrings {
{ MyClass::MyEnum::AAA, "MyClass::MyEnum::AAA" },
{ MyClass::MyEnum::BBB, "MyClass::MyEnum::BBB" },
{ MyClass::MyEnum::CCC, "MyClass::MyEnum::CCC" }
};
auto it = MyEnumStrings.find(e);
return it == MyEnumStrings.end() ? "Out of range" : it->second;
}
int main()
{
std::cout << magic(MyClass::MyEnum::AAA) <<'\n';
std::cout << magic(MyClass::MyEnum::BBB) <<'\n';
std::cout << magic(MyClass::MyEnum::CCC) <<'\n';
}
约束
- 请其他答案或基本链接没有无价值的重复。
- 请避免基于宏的膨胀，或者尝试尽量减少
#define的开销。 - 请不要手动
枚举->字符串映射。 - Please no valueless duplication of other answers or basic link.
- Please avoid bloat macro-based answer, or try to reduce the
#defineoverhead as minimum as possible. - Please no manual
enum->stringmapping. - 支持
enum值，该值从零开始的数字 - 支持负数
enum值 - 支持分段的
枚举值 - 支持
class枚举（C ++ 11） - 支持
class枚举：< type>具有任何允许的< type>（C ++ 11） - 将编译时（而非运行时）转换为字符串，
或至少在运行时快速执行（例如，std :: map并不是一个好主意...） -
constexpr（C ++ 11，然后在C ++ 14/17/20中放松） -
noexcept（C ++ 11） - C ++ 17 / C ++ 20 友好代码段
- Support
enumvalues starting from a number different from zero - Support negative
enumvalues - Support fragmented
enumvalues - Support
class enum(C++11) - Support
class enum : <type>having any allowed<type>(C++11) - Compile-time (not run-time) conversions to a string,
or at least fast execution at run-time (e.g.std::mapis not a great idea...) constexpr(C++11, then relaxed in C++14/17/20)noexcept(C++11)- C++17/C++20 friendly snippet
Constraints
一个可能的想法可能是使用C ++编译器功能在编译时使用基于可变模板类和<$ c $的元编程技巧来生成C ++代码。 c> constexpr 函数...
One possible idea could be using the C++ compiler capabilities to generate C++ code at compilation-time using meta-programming tricks based on variadic template class and constexpr functions...
推荐答案
魔术枚举仅标头库为C ++ 17的枚举（从字符串到字符串，从迭代到迭代）提供静态反射。
Magic Enum header-only library provides static reflection for enums (to string, from string, iteration) for C++17.
#include <magic_enum.hpp>
enum Color { RED = 2, BLUE = 4, GREEN = 8 };
Color color = Color::RED;
auto color_name = magic_enum::enum_name(color);
// color_name -> "RED"
std::string color_name{"GREEN"};
auto color = magic_enum::enum_cast<Color>(color_name)
if (color.has_value()) {
// color.value() -> Color::GREEN
};
有关更多示例，请查看主存储库 https://github.com/Neargye/magic_enum 。
For more examples check home repository https://github.com/Neargye/magic_enum.
该库使用编译器特有的技巧（基于 __ PRETTY_FUNCTION __ / __ FUNCSIG __ ） ，适用于Clang> = 5，MSVC> = 15.3和GCC> = 9。
This library uses a compiler-specific hack (based on __PRETTY_FUNCTION__ / __FUNCSIG__), which works on Clang >= 5, MSVC >= 15.3 and GCC >= 9.
枚举值必须在 [MAGIC_ENUM_RANGE_MIN，MAGIC_ENUM_RANGE_MAX ] 。
-
默认情况下
MAGIC_ENUM_RANGE_MIN = -128，MAGIC_ENUM_RANGE_MAX = 128。
如果默认情况下所有枚举类型都需要另一个范围，重新定义宏 MAGIC_ENUM_RANGE_MIN 和 MAGIC_ENUM_RANGE_MAX 。
If need another range for all enum types by default, redefine the macro MAGIC_ENUM_RANGE_MIN and MAGIC_ENUM_RANGE_MAX.
MAGIC_ENUM_RANGE_MIN 必须小于或等于 0 ，并且必须大于 INT16_MIN 。
MAGIC_ENUM_RANGE_MIN must be less or equals than 0 and must be greater than INT16_MIN.
MAGIC_ENUM_RANGE_ MAX 必须大于 0 ，并且必须小于 INT16_MAX 。
MAGIC_ENUM_RANGE_MAX must be greater than 0 and must be less than INT16_MAX.
如果需要其他范围用于特定的枚举类型，请为所需的枚举类型添加特殊化enum_range。
If need another range for specific enum type, add specialization enum_range for necessary enum type.
#include <magic_enum.hpp>
enum number { one = 100, two = 200, three = 300 };
namespace magic_enum {
template <>
struct enum_range<number> {
static constexpr int min = 100;
static constexpr int max = 300;
};
}
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