anchor.diff: -  ;; Defines the greater-than operator
  +  ;; Defines math
   (define eq =)
   (define (> a b) (if (< a b) nil T))
   (define (abs x) (if (< x 0) (- 0 x) x))
  
positive.code: (define string> string-greaterp)
  
  ;;; list based arithmetic
  (define +
    (let ((old+ +))
      (lambda xs (foldl old+ 0 xs))))
  
negative.code: (define (null? x) (eq? x nil))
  (define (not a) (if a nil T))
  (define (to-float a) (* a 1.0))
  
  (define (exp a n)
    (if (> n 0)
      (exp-pos a n)
      (/ 1 (exp-pos a (- 0 n)))))
  
  (define (exp-pos a n)
    (if (= 0 n)
      1
      (* a (exp a (- n 1)))))
  
  (defmacro (eval-cond c . cx)
    `(if ,c
  