프레임과 프로시저와 진리값과 인자 목록도 평가기의 데이터다.

(begin
  (define (pair-bindings variables values)
    (if (null? variables)
        '()
        (cons (cons (car variables) (car values))
              (pair-bindings (cdr variables) (cdr values)))))
  (define (make-frame variables values)
    (cons '*frame* (pair-bindings variables values)))
  (define (extend-environment variables values base)
    (cons (make-frame variables values) base))
  (define (lookup variable environment)
    (if (null? environment)
        'unbound
        (let ((record (assoc variable (cdr (car environment)))))
          (if record
              (cdr record)
              (lookup variable (cdr environment))))))
  (define (make-procedure parameters body environment)
    (list 'compound parameters body environment))
  (define global-environment
    (list (make-frame '(x) '(10))))
  (define local-environment
    (extend-environment '(x y) '(3 4) global-environment))
  (define procedure
    (make-procedure '(z) '((+ x y z)) local-environment))
  (list (lookup 'x local-environment)
        (lookup 'x global-environment)
        (lookup 'y local-environment)
        (car procedure)
        (cadr procedure)
        (length (caddr procedure))
        (length (cadddr procedure))))