Hm, am I right in thinking that numbers are defined to be atoms in lisp. And also that there are limits to how one can use macros, in that you'd not be able to a) rename FIRST, as in (FIRST list) to 1 (or '1): (1 list) or ('1 list); and b) that you couldn't modify the syntax to "decompose"/parse a slice syntax like: (1:2 (list-of-lists)) (here 1:2 would mean for example first element of second sublist/cons) ?

Now, you could of course write an interpreter for such a language in lisp, but am I correct in assuming that there's no reasonable way to get a (standard'ish) lisp to compile an expression like (1:2 ...) to the equivalent caadr(?)-like expression?

I saw there's a library for clojure that adds "slice notation" -- but does so by adding a (slice x y list)-macro which of course is fine -- but it would seem that (x:y list) would give similar benefits to the cadr/cddr etc -- allowing selected subsets to be highly optimized, for example? (As well as offering concise syntax)