- * The implementation is a bit convoluted to make sure the container is
- * evaluated only once (however, keep in mind that c.end() is evaluated
- * at every pass through the loop). To ensure the container is not
- * evaluated multiple times, the macro defines one do-nothing if
- * statement to inject the Boolean variable FOR_EACH_state1, and then a
- * for statement that is executed only once, which defines the variable
- * FOR_EACH_state2 holding an rvalue reference to the container being
- * iterated. The workhorse is the last loop, which uses the just-defined
- * rvalue reference FOR_EACH_state2.