I’ve been doing a reasonable amount of Clojure development recently and like a lot of other Lisp dialect have marveled at the ease of separately pulling out the keys and values from a map. This is a very common operation after all, but C++ does only appear to support manual key or value extraction from a std::map.

Obviously the code isn’t hard to write. In C++11, the following function will return a vector of all keys in a map: