C++如何实现反射机制 C++反射机制的模拟实现方法

#include <iostream>
#include <string>
#include <vector>
#include <map>

// 简单的元数据结构
struct FieldMeta {
    std::string name;
    std::string type;
    size_t offset; // 成员变量在类中的偏移量
};

struct MethodMeta {
    std::string name;
    // 可以添加参数类型等信息
};

struct ClassMeta {
    std::string name;
    std::vector<FieldMeta> fields;
    std::vector<MethodMeta> methods;
};

// 全局注册表
std::map<std::string, ClassMeta> g_classRegistry;

// 注册类的宏
#define REGISTER_CLASS(className) \
    static bool register_##className() { \
        ClassMeta meta; \
        meta.name = #className; \
        g_classRegistry[#className] = meta; \
        return true; \
    } \
    static bool dummy_##className = register_##className();

// 注册字段的宏
#define REGISTER_FIELD(className, fieldName, fieldType) \
    static bool register_field_##className##_##fieldName() { \
        ClassMeta& meta = g_classRegistry[#className]; \
        FieldMeta field; \
        field.name = #fieldName; \
        field.type = #fieldType; \
        field.offset = offsetof(className, fieldName); \
        meta.fields.push_back(field); \
        return true; \
    } \
    static bool dummy_field_##className##_##fieldName = register_field_##className##_##fieldName();


class MyClass {
public:
    int myInt;
    std::string myString;

    void myMethod() {
        std::cout << "MyMethod called" << std::endl;
    }

    REGISTER_CLASS(MyClass) // 注册MyClass

    MyClass() : myInt(0), myString(""){
        REGISTER_FIELD(MyClass, myInt, int) // 注册myInt字段
        REGISTER_FIELD(MyClass, myString, std::string) // 注册myString字段
    }
};


int main() {
    // 打印注册的类信息
    for (const auto& pair : g_classRegistry) {
        std::cout << "Class Name: " << pair.second.name << std::endl;
        for (const auto& field : pair.second.fields) {
            std::cout << "  Field: " << field.name << ", Type: " << field.type << ", Offset: " << field.offset << std::endl;
        }
    }

    return 0;
}