jonase/termito

Clojure term rewriting system

{
  "createdAt": "2013-03-16T19:42:19Z",
  "defaultBranch": "master",
  "description": "Clojure term rewriting system",
  "fullName": "jonase/termito",
  "homepage": null,
  "language": "Clojure",
  "name": "termito",
  "pushedAt": "2013-03-18T18:59:34Z",
  "stargazersCount": 35,
  "topics": [],
  "updatedAt": "2022-07-04T17:36:30Z",
  "url": "https://github.com/jonase/termito"
}

termito

Termito is a simple term rewriting library for clojure. It is inspired by the kibit rule system but with more features.

Usage

Add [jonase/termito 0.0.1] to your dependencies in project.clj.

Example

Here are some simple arithmetic rules:

(defrules zero-rules
  [(* 0 ?x) 0])

(defrules identity-rules
  [(* 1 ?x) ?x]
  [(+ 0 ?x) ?x])

(def rules (concat zero-rules
                   identity-rules)

(simplify '(+ (* 0 x) (* 1 y)) rules)
;; => y

More advanced examples can be found in [src/termito/examples]!(src/termito/examples). For example, combining the [arithmetic rules]!(src/termito/examples/arithmetic.clj) with the following derivative rules

(defrules derivative-rules
  [(D (pow ?x ?n) ?x) (* ?n (pow ?x (- ?n 1)))]
  [(D (* ?a (pow ?x ?n)) ?x) (* ?a (D (pow ?x ?n) ?x))])

termito can solve simple math problems like “what is the second derivative of 5x^3”:

=> (simplify '(D (D (* 5 (pow x 3)) x) x)
             (concat arithmetic/rules derivative-rules)))
(* 30 x)

License

Distributed under the Eclipse Public License, the same as Clojure.