Implementation C++14 make_integer_sequence

Question

I tried to implement the C++14 alias template make_integer_sequence, which simplifies the creation of the class template integer_sequence.

templ         


        

Answer 1

Here's a log N implementation that doesn't even need an increased max-depth for template instantiations and compiles pretty fast:

// using aliases for cleaner syntax
template using Invoke = typename T::type;

template struct seq{ using type = seq; };

template struct concat;

template
struct concat, seq>
  : seq{};

template
using Concat = Invoke>;

template struct gen_seq;
template using GenSeq = Invoke>;

template
struct gen_seq : Concat, GenSeq>{};

template<> struct gen_seq<0> : seq<>{};
template<> struct gen_seq<1> : seq<0>{};