(define tree (lambda (x) (let Y ((x x)) (if (null? (cdr x)) (car x)
  (Y (let pair ((x x)) (if (null? x) '()
     (cons (cons (car x) (cadr x)) (pair (cddr x))))))))))

defaults write com.barebones.textwrangler BalanceIncludesDelimiters -bool YES
http://www.barebones.com/support/develop/clm.html

(let ((rnk (((fileVal "gRREF") zero? 0 1 / * - #f) 'rank)))
  (letrec ((bas (lambda (n) (cdr (let I ((n n)) (if (= n 0) (cons 0 (list 1))
 ; (I n) returns a pair:
 ; zero in C(n) and a list of 2^n basis vectors in C(n).
   (let* ((J (I (- n 1))) (Z (car J)) (lo (cdr J))) (cons (cons Z Z) 
   (append (map (lambda (o) (cons Z o)) lo) (map (lambda (o) (cons o Z)) lo)))))))))
     (fl (lambda (c) (if (pair? c) (append (fl (car c)) (fl (cdr c))) (list c)))))
  (ylppa (fileVal "Clifford2") (lambda (G reals)
    (ylppa (G (G (G (G (cons '() reals)))))
      (lambda (sg / tr bar alpha zer one + ng * rls basis)
        (ylppa basis (lambda (g0 g1 g2 g3)
  (let ((fun (lambda (a b) (let ((bm (map (lambda (x) (fl (* x a))) (bas 4))))
      (list (equal? zer (* a b)) (rnk bm))))))
  (list
    (let ((p (* g0 g1))) (fun (+ p g2) (+ p (ng g2))))
    (fun (+ g3 (* g0 (* g1 g2))) (+ g1 (* g0 (* g2 g3))))
    (let ((p (* (* g0 g1) (* g2 g3)))) (fun (+ one p) (+ one (ng p)))))
))))))))) ; => ((#t 8) (#t 8) (#t 8))