Toys

gistfile1.clj

;; learning The Little Schemer
;; Chapter 1. Toys
(def car first)
(def cdr rest)
(def cons clojure.core/cons)
(def eq? =)
(def list? clojure.core/list?)
(def atom?
  (fn [x]
    (not (list? x))))

(def s-exp? 
  (fn [x]
    (or (atom? x) (list? x))))

(def null?
  (fn [x]
     (if (atom? x) (car x)    ;raise a exception
        (and (list? x) (empty? x)))))

try use gist