I''m actually working on a Lisp interpreter now. What type of game is it? All in all, I think you could get away with not implementing those features, as its really up to you what you need anyway. Cheers.

If a plant cannot live according to its nature, it dies; so a man.

This may be interesting to you.

Really, I''d suggest you just implement types/functions/macros/etc as you find need for them. If you wrote it to be modular, it shouldn''t be too difficult, and it saves time if you end up not needing something. Off gut feeling, I''d say you probably wont need the things you listed. You don''t need Common Lisp for a simple scripting language. If you decide you want a bit string for ex, you could just use an array of boolean values (or even integers with 0/1). I think a lot of the functionality of Common Lisp is a holdover from ways of the past(or some other issue that you don''t have) and unless your purpose is implementing Common Lisp, just put in whatever you feel like. Just keep the syntax, macros, ''eval'' and a few other things and you should be good to go for a powerful scripting language. You might want to browse through Common Lisp the Language, 2nd Edition if you haven''t already and read the suggestions/ideas/etc put in there. A lot of things were up for change when it was written, and some of them that weren''t chosen would make for a better language imo.