anchor.diff:                          ((numbered-placeholder? f e)
                            (values (make-var/numbered f) t))
                           ((and (listp f) (some (lambda (x) (rest-placeholder? x e)) f))
  -                         (let ((f (cons (car f) (mapcar (lambda (x) (walk-op x e)) (cdr f)))))
  +                         (let ((f (cons (car f)
  +                                        (mapcar (lambda (x) (walk-op x e))
  +                                                (cdr f)))))
                              (values
                               (make-spliced-call f e)
                               t)))
  
positive.code:                             y)))
                       (t x))))
        (declare (ignorable #'quotation?))
        (let ((body (walk-op `(progn ,@body) env))
              (rest
                (and (rest-op? `(progn ,@body) env)
                     `(&rest ,(intern (string '_*))))))
          `(lambda (,@(reverse vars) ,@rest)
             (declare (ignorable ,@vars))
  
negative.code: (in-readtable :standard)
  
  ;; TODO Handle dotted lists.
  (defmacro op (&body body &environment outer-env)
    "GOO's simple macro for positional lambdas.
  
  An OP is like a lambda without an argument list. Within the body of the OP
  