anchor.diff:  
   (defpackage clep
     (:use :cl)
  -  (:export :clep))
  +  (:export
  +   :clep-file
  +   :clep-sexp))
   
   (in-package :clep)
   
  
positive.code:     (match-search pattern (car tree) matched-fn)
      (match-search pattern (cdr tree) matched-fn)))
  
  (defun clep-file (pattern filename)
    (with-open-file (in filename)
      (let ((acc))
        (loop :with eof-value := (gensym)
  
negative.code:                            (list arg)))
                       args))))
      (loop :for filename :in filenames
        :append (clep-file-internal pattern filename))))
  
  (defun clep-sexp (pattern x)
    (let ((acc))
      (match-search pattern x
                    #'(lambda (tree binds)
                        (push (list tree binds) acc)))
      (nreverse acc)))
  