anchor.diff:                       (eq (car body) (car args))
                        (not (eq (cadr body) (car args)))
                        (symbolp (cadr body)))))
  -         `(,(β-reduce (cadr form))
  +         `(,(cadr form)
              ,(cadr (caddr (car form)))))
   
           ; (identity x) => x
           ((eq (car form) *top-k*)
  -         (β-reduce (cadr form)))
  +         (cadr form))
   
           ; uncurry:
           ; ((lambda (p1) ((lambda (args...) body) exprs...)) s) =>
  
positive.code:       (any (lambda (p) (contains x p)) form)))
  
  (define (β-reduce form)
    (cond ((or (atom form) (constantp form)) form)
  
          ; ((lambda (f) (f arg)) X) => (X arg)
          ((and (= (length form) 2)
                (consp (car form))
                (eq (caar form) 'lambda)
                (let ((args (cadr (car form)))
  
negative.code:                               ,s
                                ,@params)))))))
  
          (T form)))
  
  (defmacro with-delimited-continuations code (cps (f-body code)))
  
  