anchor.diff:  
   (defpackage clep
     (:use :cl)
  -  (:export :clep))
  +  (:export
  +   :clep-file
  +   :clep-sexp))
   
   (in-package :clep)
   
  
positive.code:                            (list arg)))
                       args))))
      (loop :for filename :in filenames
        :append (clep-file pattern filename))))
  
negative.code:     :when (equal "lisp" (pathname-type pathname))
      :collect (namestring pathname)))
  
  (defun clep-file (pattern &rest args)
    (let ((filenames
           (if (null args)
               (collect-lisp-files)
  