Lab 19: Rule Based Systems
    
      - Get Clips running. It's on 
           
	    http://clipsrules.sourceforge.net.  Go to download;
            I got clips_windows_executables_630.zip, and extracted
            CLIPSIDE32.exe.
 
       - Run that, and you get the clips shell. 
 
       - Assert some facts (assert (duck)) (facts) 
 
       - Make some rules.  Open up a file, (defrule bob (duck) => 
	 (assert (chicken))).  Load it in, run.
       
 
   - Now make some assertions that define a hierarchy of mammals. 
       You can do it in a variety of ways, but I used facts that looked
       like (ISA canine mammal). 
 
   - Make sure that you have some grand-children nodes, like (ISA wolf
       canine). 
 
   - Make a rule which expands the ISA relation.  In my case it added the
       fact (ISA wolf mammal).
 
   - Now add some feature facts.  For example (feature blood mammal warm).
       Only add them in the appropriate place in the hierarchy.  (IE don't 
       also say (feature blood canine warm).
 
   - Now add a rule which exploits the ISA relations to put these
       facts in.
 
   - If you haven't already done so, add an initial rule that puts your 
       basic facts in the system, reset and see what you get.  You should
       also save your rules into a .clp file, clear, reset, load the file,
       and run and see what you get. 
 
   - Now implement overriding inheritence.  For instance, by default
       mammals travel by walking, but bats do not.  I did this by
       modifying my feature inheritence rule.
 
   - Now add enough nodes so that it expands to over 100 facts. (I did
       it with 20 facts, but I'm sure I could have used less.)
 
   - Can you implement any other interesting rules like one that only
       prints out the facts for one type animal, or prints out all
       the subclasses of an animal?