And the easiest way to leverage that effort is to use CL as an implementation platform. Whatever you think of CL as a language to program in directly, it reall

And the easiest way to leverage that effort is to use CL as an implementation platform. Whatever you think of CL as a language to program in directly, it really shines as a language to implement dynamic languages in. You get a lot of useful pieces, including native-code compilation, some very powerful control-flow operators, multithreading (in most implementations), and of course garbage collection, for free. There's a more subtle benefit as well. Because compilability was a key goal in the design of CL, using it as a translation target while you're designing a new dynamic language will help you make sure your language is also efficiently compilable. EDITED to add: in CL, the whole tagged-pointer thing has been taken care of for you, so you don't have to think about it (cf. [0]). This means you get fixnums (unboxed immediate integers), with automatic overflow to bignums (arbitrary-precision integers), for free. In fact there's the whole CL numeric tower, including ratios and complex numbers. Other goodies: multiple inheritance. Multimethods (multiple dispatch). Class creation and redefinition at runtime. It baffles me that anyone would want to reimplement all that stuff, or even part of it. [0] https://mail.python.org/pipermail/python-dev/2004-July/046147.html https://mail.python.org/pipermail/python-dev/2004-July/04614...