C++11 可变参数模板构造string列表

#include <iostream>
#include <cstdint>
#include <list>
#include <string>

template<typename T>
typename std::enable_if<std::is_integral<T>::value, std::string>::type to_string(const T & val)
{
        return std::to_string(val);
}
template<typename T>
typename std::enable_if<std::is_floating_point<T>::value, std::string>::type to_string(const T & val)
{
        return std::to_string(val);
}
template<typename T>
typename std::enable_if<std::is_enum<T>::value, std::string>::type to_string(const T & val)
{
        return std::to_string(val);
}
std::string to_string(const std::string & val)
{
        return val;
}
std::string to_string(char * val)
{
        return val;
}

template<typename T>
void build_str_list(std::list<std::string> & ret, const T & val)
{
        ret.push_back(to_string(val));
}

template<typename T, typename... Args>
void build_str_list(std::list<std::string> & ret, const T & head, Args&&... args)
{
        ret.push_back(to_string(head));
            build_str_list(ret, args...);
}

template<typename... Args>
std::list<std::string> build_string_list(Args&&... args)
{
        std::list<std::string> ret;
        build_str_list(ret, args...);
        return ret;
}

int32_t main()
{
    int16_t a = ;
    uint16_t b = ;
    int32_t c = ;
    int64_t d = ;
    uint32_t e = ;
    uint64_t f = ;
    std::string str = "thank";
    const char * you = "you";
    char buf[] = "asd";
    enum
    {
       ENUM_A = ,
    };
    std::list<std::string> ret = build_string_list(, "hehe", a, b, c, d, e, f, str, you, ENUM_A, "", buf);
    for (const std::string & str : ret)
    {
      std::cout << str << std::endl;
    }
    return ;
}