anchor.diff:  				   (setf nodes (cons (car n) nodes))
   				   (retreive-nodes (append (cdr n) (lset-difference eq
   										    (node-destinations (car n))
  -										    nodes)))))
  -			       (build-fsa-builder-with-nodes
  -				(lambda ()
  -				  (for-each (lambda (node)
  -					      (fsa-add-node! fsa-builder node))
  -					    nodes)))))
  +										    nodes))))))
  +	       (build-fsa-builder-with-nodes
  +		(lambda ()
  +		  (for-each (lambda (node)
  +			      (fsa-add-node! fsa-builder node))
  +			    nodes))))
   	      (retreive-nodes nodes))
         fsa-builder))
   
  
positive.code:     fsa))
  
  (defun fsa-remove-edge! (fsa src-label input-symbol dst-label)
    (let ((src-node (hash-table-ref/default (fsa-builder-nodes fsa) src-label #f))
  	(dst-node (hash-table-ref/default (fsa-builder-nodes fsa) dst-label #f)))
      (if (and src-node dst-node)
  	(node-remove-edge! src-node input-symbol dst-node))
      fsa))
  
negative.code: (defun graphviz-export-to-file (fsa file) 
    "This function will write the dot description of the FSA in the stream."
    (let ((p (open-output-file file)))
      (format p "digraph G {~%  rankdir = LR;~%  size = \"8, 10\";~%") 
      (if (not (null? (fsa-builder-finals fsa)))
  	(progn
  	  (format p "~%  node (shape = doublecircle);~% ")
  	  (map (lambda (x) 
  		 (format p " \"~A\"" (node-label x)))
  	       (fsa-builder-finals fsa))
  	  (foramt p ";")))
      (format p "~%~%  node (shape = circle);~% ")
      (map (lambda (label)
  	   (format p " \"~A\"" label))
  	 (hash-table-keys (fsa-builder-nodes fsa)))
      (format p ";~%~%")
      (map (lambda (node)
  	   (map (lambda (edge)
  		  (format p 
  			  "  \"~A\" -> \"~A\" (label = \"~A\");~%"
  			  (car edge)
  			  (caddr edge)
  			  (if (null? (cadr edge))
  			      "epsilon"
  			    (cadr edge))))
  		(node-edges node)))
  	 (hash-table-values (fsa-builder-nodes fsa)))
      (format p "}~%") 
      (close-output-port p)
      fsa))
  
  