Why isn't a for-loop a compile-time expression?

Question

If I want to do something like iterate over a tuple, I have to resort to crazy template metaprogramming and template helper specializations. For example, the following progr

Answer 1

Why isn't a for-loop a compile-time expression?

Because a for() loop is used to define runtime control flow in the c++ language.

Generally variadic templates cannot be unpacked within runtime control flow statements in c++.

 std::get(t);

cannot be deduced at compile time, since i is a runtime variable.

Use variadic template parameter unpacking instead.

---

You might also find this post useful (if this not even remarks a duplicate having answers for your question):

iterate over tuple