quasiquote for primitive lisp

I was searching for a basic quasiquote implementation in lisp which mentioned a paper by Alan Bawden. Anyway it was difficult to find via google so I figured I would type it up here for posterity. The original paper can be found: here.

(define (qq-expand x)
  (cond ((tag-comma? x)
         (tag-data x))
        ((tag-comma-atsign? x)
         (error "Illegal"))
        ((tag-backquote? x)
         (qq-expand (qq-expand (tag-data x))))
        ((pair? x)
         `(append ,(qq-expand-list (car x))
                  ,(qq-expand (cdr x))))
        (else '', x)))

(define (qq-expand-list x)
  (cond ((tag-comma? x)
         `(list ,(tag-data x)))
        ((tag-comma-atsign? x)
         (tag-data x))
        ((tag-backquote? x)
         (qq-expand-list (qq-expand (tag-data x))))
        ((pair? x)
         `(list (append ,(qq-expand-list (car x))
                        ,(qq-expand (cdr x)))))
        (else ''(,x))))