c++ - Apply a (sort of a meta) function to a sequence of types -

i have function:

template <typename t> std::string foo(); 

which think of taking type input , producing string.

i have either parameter pack, or tuple, more convenient you; suppose it's

using std::tuple<myparameters...> my_types; 

now, want invoke foo<t> on each type t in pack, or in tuple's type definition, in sequence.

i realize can using library such boost's mpl or boost hana, don't want stick of code, , wondering if principle of doing "captured" in succinct.

notes:

• bonus points if provide answer works generic lambda's instead of templated function.
• answer must c++14, not c++17.

imho, sort of things need partial specialization. struct/classes, non functions.

so if can demand work method of variadic struct bar, can write foo() calling method in bar (the operator(), example) follows

template <typename t> std::string foo ()  { return bar<t>()(); } 

the following full working (i don't know if "succinct" enough) example; it's c++11, if i'm not wrong.

#include <tuple> #include <complex> #include <iostream>  template <typename ...> struct bar;  template <typename t0, typename ... ts> struct bar<t0, ts...>  {    std::string operator() ()     { return "type; " + bar<ts...>()(); }  };  template <template <typename ...> class c,           typename ... ts1, typename ... ts2> struct bar<c<ts1...>, ts2...>  {    std::string operator() ()     { return "type container; " + bar<ts1...>()() + bar<ts2...>()(); }  };  template <> struct bar<>  { std::string operator() () { return {}; } };  template <typename t> std::string foo ()  { return bar<t>()(); }  int main ()  {    std::cout << foo<int>() << std::endl;    std::cout << foo<std::tuple<int, long, short, std::tuple<long, int>>>()       << std::endl;    std::cout << foo<std::complex<double>>() << std::endl;  } 

p.s.: isn't clear me mean "an answer works generic lambda's instead of templated function".

can show example of use?