the limitation of luple

[shenxiaolong-code]

1. the member type MUST be one of type_list_t
   using type_list_t = type_list<
   void *, bool, char, unsigned char, signed char, short, int, long, long long,
   unsigned short, unsigned int, unsigned long, unsigned long long,
   float, double, long double
   >;
   e.g. unsupported type case:
   struct myStruct ;
2. the membere type MUST be different.
   e.g. unsupported case :
   struct myStruct {
   int v1;
   int v2;
   int v3;
   }

based on your code, I am trying to break those limitation :)
if possible , please enhance it -- it is helpful.