I have a container which (among other things) exposes a string buffer, and the upper case version of that string buffer. (Well, it isn't just upper case, but it is similar in concept) I want to allow a caller to do something similar to:
container c("Example");
auto const iter = c.begin() + 2;
std::printf("%c\n", iter->get_source()); // Prints a
std::printf("%c\n", iter->get_upper()); // Prints A
iter->set('x');
std::puts(c.get()); // Prints Exxmple
std::puts(c.get_upper()); // Prints EXXMPLE
The problem is, the "proxy" type with the member functions get_source, get_upper, etc. has no obvious place it can be stored, and an iterator is required to return a reference to something, not a value. (vector<bool> has a similar problem)
Alternately I could expose some kind of shell container or range, or expose completely separate iterator begin/end functions. Does anyone have experience doing something like this and know what works well?