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From: creeds@hardy.u.washington.edu (Ron Legere)
Newsgroups: comp.theory
Subject: Rule Based Language.
Message-ID: <19046@milton.u.washington.edu>
Date: 26 Mar 91 07:11:50 GMT
Sender: news@milton.u.washington.edu
Reply-To: creeds@hardy.acs.washington.edu (Ron Legere)
Organization: University of Washington, Seattle
Lines: 32



I am not sure that this belongs in this group but here goes:

I was recently playing around with a product called "Mathamatica".

What struck me as interesting was its method of programming by
"Transformation rules."

My question is are there  any languages that are based on this idea.
I guess in its most basic form ( not mathamatical like mathamatica)
 you would be allowed to enter rules:
   
   swap $a $b -> b a
 ( Where the $a for example indicates that any  string can  fill 
the pattern, and the thing filling it is temp. called a) 
 Then when you enter an expression like
 swap x y 
The system would search the defined rules and return:
  y x
Recursion should also be allowed. 
The system should also keep evaluating rules until it ran out of rules,
and I suppose some precedence would be needed.
Are there any languages like this? Are there any languages that can 
easily be made to emulate this? Please NOTE: I am not a CS student!
Also , Is the above, when fleshed out enough to define a full language?
( in the Turing equivalence sense ) 
 
                      Please Respond By Email:
   creeds@hardy.u.washington.edu 

Ron Legere