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core.clj
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core.clj
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(ns kibit.core
"Kibit's core functionality uses core.logic to construct idiomatic
replacements/simplifications for patterns of code."
(:require [clojure.walk :as walk]
[clojure.core.logic :as logic]))
;; ### Important notes
;; Feel free to contribute rules to [kibit's github repo](https://github.com/jonase/kibit)
;; Building an alternative form
;; ----------------------------
;;
;; ### Applying unification
;;
;; Performs the first simplification found in the rules. If no rules
;; apply the original expression is returned. Does not look at
;; subforms.
(defn simplify-one [expr rules]
(let [alts (logic/run* [q]
(logic/fresh [pat subst]
(logic/membero [pat subst] rules)
(logic/project [pat subst]
(logic/all (pat expr)
(subst q)))))]
(if (empty? alts) expr (first alts))))
;; Simplifies expr according to the rules until no more rules apply.
(defn simplify [expr rules]
(->> expr
(iterate (partial walk/prewalk #(simplify-one % rules)))
(partition 2 1)
(drop-while #(apply not= %))
(ffirst)))