which - find binary on PATH accounting for PATHEXT on Windows - (JVM Clojure and babashka)

which.clj

(require '[clojure.java.io :as cji])
(require '[clojure.string :as cs])

(defn which
  [bin-name]
  (let [paths (clojure.string/split (or (System/getenv "PATH") "")
                (re-pattern (System/getProperty "path.separator")))
        ;; for windows
        pathexts (clojure.string/split (or (System/getenv "PATHEXT") "")
                   (re-pattern (System/getProperty "path.separator")))]
    ;; adapted work by taylorwood
    (first
      (for [path (distinct paths)
            pathext pathexts
            :let [exe-file (clojure.java.io/file path (str bin-name pathext))]
            :when (.exists exe-file)]
        (.getAbsolutePath exe-file)))))