We often hear that Common Lisp is dynamically typed, which is not wrong, but that leads to the belief that Lisp is as bad as Python concerning types, which is plainly wrong. We don’t hear enough that CL is a compiled language, that we can add type annotations, and that SBCL does thorough type checking. Hence, what we have at hand is awesome: we can compile a whole program or compile a single function and get type warnings.
