Provide an interface that mimics Python's enumerate() or Go's range()

[aary]

The goal is to copy Python's enumerate() utility

range = [1, 2, 3, 4]
for element, index in enumerate(range):
    print index + " : " + element

or Go's range keyword

for index, element := range someSlice {
    fmt.Println(index, element)
}

In C++ this might look like the following

auto vec = std::vector<int>{1, 2, 3, 4};
for (auto [element, index] : sharp::enumerate(vec)) {
    cout << index << " : " << element << endl;
}

This code will work in C++17 with structured bindings, but will not work with C++14. The closest behavior in C++14 is with std::tie()

auto range = std::vector<int>{1, 2, 3, 4};
auto integer = int{};
auto index = std::size_t{};
for (std::tie(integer, index) : sharp::enumerate(range)) {
    cout << index << " : " << element << endl;
}

This is also fine till support for C++17 is common. Then it will be easy to switch to the nice structured bindings syntax.