common.lisp

(define null? not)
(define err? (lambda (x) (eq? x 'ERR)))
(define number? (lambda (x) (eq? (* 0 x) 0)))
(define pair? (lambda (x) (not (err? (cdr x)))))
(define symbol?
    (lambda (x)
        (and
            x
            (not (err? x))
            (not (number? x))
            (not (pair? x)))))
(define atom?
    (lambda (x)
        (or
            (not x)
            (symbol? x))))
(define list?
    (lambda (x)
        (if (not x)
            #t
            (if (pair? x)
                (list? (cdr x))
                ()))))
(define equal?
    (lambda (x y)
        (or
            (eq? x y)
            (and
                (pair? x)
                (pair? y)
                (equal? (car x) (car y))
                (equal? (cdr x) (cdr y))))))
(define negate (lambda (n) (- 0 n)))
(define > (lambda (x y) (< y x)))
(define <= (lambda (x y) (not (< y x))))
(define >= (lambda (x y) (not (< x y))))
(define = (lambda (x y) (eq? (- x y) 0)))
(define list (lambda args args))
(define cadr (lambda (x) (car (cdr x))))
(define caddr (lambda (x) (car (cdr (cdr x)))))
(define begin (lambda (x . args) (if args (begin . args) x)))