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From: des0mpw@colman.newcastle.ac.uk (M.P. Ward)
Newsgroups: comp.lang.lisp
Subject: Looking for an expression simplifier
Message-ID: <1991Jan23.121653.3607@newcastle.ac.uk>
Date: 23 Jan 91 12:16:53 GMT
Sender: news@newcastle.ac.uk
Organization: Computing Laboratory, University of Newcastle upon Tyne, UK, NE1 7RU
Lines: 27

I am looking for some CL code to simplify expressions (input as lisp structures
eg: (+ B A (+ C B))). Nothing very clever, just the sort of expressions
found in simple programs. This is for our research project on programs
transformation/analysis.

Some examples:

(+ B A (+ C B)) simplifies to (+ A B C) 

(* (+ A B) (- A B))  simplifies to (- (^ A 2) (^ B 2))

(- (* (+ A B) (- A B)) (- (^ A 2) (^ B 2))) simplifies to 0

I hope you get the idea. Ideally it would be extensible, based on a list of
rules which could be added to.

I have the source for the Boyer-Moore Theorem Prover and Maxima, but we
are finding it a bit difficult to dig out the parts we could make use of.

Please email replies as I don't often read this list. Many thanks!

		Martin.

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