A Constant Range of Modifiable Elements

Kilian Henneberger reminded me of a special use case of std::span, i.e., a constant range of modifiable elements.

For simplicity, I name a std::vector and a std::span a range. A std::vector, like an std::string models a modifiable range of modifiable elements: std::vector<T>. When you declare this std::vector as const, the range models a constant range of constant objects: const std::vector<T>. You cannot model a constant range of modifiable elements. Here comes std::span into play. A std::span models a constant range of modifiable objects: std::span<T>.

The following table emphasizes the variations of (constant/modifiable) ranges and (constant/modifiable) elements.