feat(prelude): add define/defun

src/bin/demo.rs

@@ -13,6 +13,8 @@ fn main() {
         "(pow 2 10)",
         "(let '((fib . (lambda (n) (if (< n 2) n (+ (fib (- n 1)) (fib (- n 2))))))) (fib 10))",
         "(let '((a . (vec3 1 2 3)) (b . (vec3 4 5 6))) (vec3-dot (vec3-norm (vec3-add a b)) a))",
+        "(defun do-n-times (f n) (if (= n 0) '() (cons (f) (do-n-times f (- n 1)))))",
+        "(do-n-times (lambda () (print 'hello)) 5)",
     ];
 
     let environment = Environment::default();