String distance function

strdist.clj

(ns strdist
(:require [clojure.core.match :refer [match]]
          [clojure.string :as str]))

(defn -distance
  [s1 s2]
  (match [s1 s2]
    [nil    _] (.length s2)
    [_    nil] (.length s1)
    [([l & ls] :seq) ([r & rs] :seq)] (min (+ (if (= l r) 0 1) (-distance ls rs))
                                           (+ 1 (-distance ls s2))
                                           (+ 1 (-distance s1 rs)))
    :else 0))

(defn distance
  [s1 s2]
  (-distance (seq s1) (seq s2)))

(comment
  (distance "abc" "dec")
  (distance "aaa" "bbb")
)