edn->json command-line script + emacs interactive function interface

edn2json.cljs

#!/usr/local/bin/planck

(ns scripts.edn2json
  (:require [cljs.reader :as r]
            [planck.core :refer [slurp *command-line-args* *in* line-seq]]))

(defn last-n-chars [n s]
  (apply str (reverse (take n (reverse s)))))

(let [s (first *command-line-args*)
      edn (if (#{".edn" ".clj"} (last-n-chars 4 s))
            (slurp s)
            (or s
                (apply str (line-seq *in*))))]
  (->> edn
       r/read-string
       clj->js
       (.stringify js/JSON)
       println))

edn2json.el

(defmacro defshellonreg (name cmd &optional replace)
  `(defun ,name (beg end)
     (interactive "r")
     (shell-command-on-region beg end ,cmd
                              (if ,replace (current-buffer) nil)
                              ,replace)))

;; ...

(defshellonreg edn->json "edn2json.cljs" t)

;; {:foo :bar, :baz 1}   =>  {"foo":"bar","baz":1}