I think it's unfortunate that more people aren't aware of the benefits of using Common Lisp as an implementation target for their new language. All you have to do is to parse your language into list structure and write macros to translate it into Lisp. You get an interpreter <i>and</i> a native-code compiler for free! And there's a long list of language features for you to build on: GC of course, plenty of built-in types (including lists, arrays, and several kinds of numbers) -- and the crown jewel, CLOS, with multiple inheritance, multiple dispatch, and of course, the MOP.<p>I understand why a lot of people aren't interested in writing CL directly -- though I am still fond of it; it does suffer somewhat from historical baggage. But if you're layering another language on top of it, none of that matters. And it's a great platform.