anchor.diff:      :when (equal "lisp" (pathname-type pathname))
       :collect (namestring pathname)))
   
  -(defun clep (pattern &rest args)
  +(defun clep-file (pattern &rest args)
     (let ((filenames
            (if (null args)
                (collect-lisp-files)
  
positive.code: 
  (defpackage clep
    (:use :cl)
    (:export :clep))
  
  (in-package :clep)
  
  
negative.code:     (match-search pattern (car tree) matched-fn)
      (match-search pattern (cdr tree) matched-fn)))
  
  (defun clep-file-internal (pattern filename)
    (with-open-file (in filename)
      (let ((acc))
        (loop :with eof-value := (gensym)
  