There is a bit more to it. It allows one to create mixed C++ / Lisp projects with memory management, CLOS methods for C++ classes, CLOS subclass of C++ classes,

There is a bit more to it. It allows one to create mixed C++ / Lisp projects with memory management, CLOS methods for C++ classes, CLOS subclass of C++ classes, Lisp and C++ gets compiled to LLVM-IR, debug source output mixing compiled C++ and Lisp frames, ...