import std.stdio, std.traits, std.meta, std.range, std.algorithm;

​

struct D(Ds...) {

  enum int[Ds.length] dims = [Ds];

}

​

struct Tensor(T, D) {

}

​

auto permute(T, int N)(T[N] xs, T[N] ps) {

  T[N] result;

  foreach (i, p; ps)

    result[i] = xs[p];

  return result;

}

​

auto permute(P, T, A)(Tensor!(T, A)) {

  assert([7, 3, 5] == permute(A.dims, P.dims));

  return Tensor!(T, D!(aliasSeqOf!(permute(A.dims, P.dims))))();

}

​

unittest {

  const x = Tensor!(int, D!(3, 5, 7))();

  const y = permute!(D!(2, 0, 1))(x);

  assert(is(Unqual!(typeof(y)) == Tensor!(int, D!(7, 3, 5))));

}

​