YOMM2_GENSYM
defined in <yorel/yomm2/symbols.hpp>, also provided by <yorel/yomm2/keywords.hpp>
YOMM2_GENSYM expands to a new C++ identifier each time it is called. The
symbol is based on the __COUNTER__ preprocessor macro, and decorated in such a
way that it is unlikely to clash with user-defined symbols.
YOMM2_GENSYM provides a convenient way of allocating static
objects for registering classes, methods, or definitions.
int YOMM2_GENSYM;
int YOMM2_GENSYM; // not a redefinition, this is a new symbol