Well, there are a lot of those, they need to be looked at separately. What I (and the QPX school if I might use the term) use is compile-time computing, aka a

Well, there are a lot of those, they need to be looked at separately. What I (and the QPX school if I might use the term) use is compile-time computing, aka a programmable programming language. LLVM never gets to see this, by the time you pass it to the compiler it is dumb code. QPX after macroexpansion looked like C. When it comes to executing code that only becomes available at run time (repl, eval, from a string, from a file etc) you generally just kick off the compiler, which is that Clasp and LLVM do right now. You can also use the interpreter which again both Clasp and SBCL have. When it comes to the dynamic nature of CLOS method invocation, that is generally accelerated with special dispatch mechanism that live in the compilers. You can implement CLOS without any compiler support, but teaching the compiler about method dispatch makes it faster. The Lisp compilers emit abstract assembly code for LLVM or the last stage of SBCL. When talking about dynamic typing the same applies. The compilers that do Lisp emit abstract machine language, pretty much the same way for Clasp and SBCL. To Clarify, Clasp uses various LLVM compilation targets including LLVM's "JIT" for runtime known code. I am not sure I'd call it a JIT because it doesn't compile functions when they are used, but they are compiled into memory (as opposed to into object files). Hope this helps.