I was very surprised to see the results for common lisp. As I scrolled down I just figured that the language was not included until I saw it down there. I would have guessed SBCL to be much faster. I checked it out locally and got: Rust 9ms, D: 16ms, and CL: 80ms.

Looking at the implementation, only adding type annotations, there was a ~10% improvement. Then the tag-map using vectors as values which is more appropriate than lists (imo) gave a 40% improvement over the initial version. By additionally cutting a few allocations, the total time is halved. I'm guessing other languages will have similar easy improvements.