anchor.diff:  	   :links-to-node 
   	   :link-remove 
   	   :link-get-types
  -	   :link-match))
  +	   :link-match
  +	   :clear-db))
   
   (in-package :proto-graph)
   
  
positive.code: (defpackage :proto-graph 
    (:use :common-lisp)
    (:export :get-keys
  	   :all-nodes
  	   :all-links
  	   :node-create
  
negative.code: 		  (links-with-type of-type links))
  	(if properties (remove-if-not #'meets-filter links)
  	    links))))
  
  ;;; General database management.
  (defun clear-db ()
    "Clears the dabase nodes and links"
    (setf *nodes* nil)
    (setf *links* nil))
  