anchor.diff:    (:method (point (name symbol) (frame frame))
       (setf (gethash name (points frame)) point)))
   
  -(defun markers (frame)
  +(defmethod markers ((frame frame))
     (loop for marker being the hash-keys of (points frame)
           collect marker))
   
  
positive.code: (in-package #:vicon-parser)
  
  (defun translate-name (name)
    (flet ((r (search replace data)
  
negative.code: (defun map-read-vicon-frames (stream vicon-file function)
    (loop for line = (read-clean-line stream)
          while line
          do (unless (string= line "")
               (let ((frame (with-retry-restart (retry "Retry parsing the line ~s" line)
                              (parse-frame (cl-ppcre:split "," line) vicon-file))))
                 (with-retry-restart (retry "Retry calling the frame mapping function.")
                   (funcall function frame))))))
  
  (defun parse-vicon-file (pathname &key (external-format :default))
    (with-open-file (stream pathname :direction :input :external-format external-format)
  