type_t implementation and example

type_t.h

template<class T, typename... Ts>
using type_t = T;

// Alternative implementation for compilers before
// [CWG 1558](http://open-std.org/JTC1/SC22/WG21/docs/cwg_defects.html#1558)
// template<class T, typename... Ts> struct type_t_impl { typedef T type;};
// template<class T, typename... Ts> using type_t = typename type_t_impl<T, Ts...>::type;


// Usage example:

// A bunch of overloads:
void encode(SomeType& out, const AnotherType& in);
void encode(SomeOtherType& out, const YetAnotherType& in);
// ...

// Generic wrapper which is SFINAE-friendly and does not require introducing extra traits:
template<class Out, class In>
inline auto encode_to(In&& in) -> type_t<Out, decltype(encode(std::declval<Out&>(), std::forward<In>(in)))>
{
    Out out;
    encode(out, std::forward<In>(in));
    return out;
}