引数に応じて関数を切り替えるだけ

joyn.clj

;; https://github.com/jiro4989/joyn の処理をClojureで書こうとして途中で飽きた

(ns joyn-clj.core
  (:require [clojure.string :as str])
  (:require [clojure.edn :as edn]))

(defn char-to-fields
  "1-15とかを1,2,3...15にする"
  [ch]
  (->> (str/split ch #",")
       (map edn/read-string)
       (map dec)))

(defn get-str-with-char
  ""
  [s poses]
  (->> poses
       (map #(nth s %))
       (apply str)))

(defn cut-char
  "Cut line with char"
  [s ch]
  (get-str-with-char s (char-to-fields ch)))

(defn cut-field
  "Cut line with char"
  [s delim field]
  (let [x (str/split s delim)]
    (if (<= (count x) field)
      ""
      (nth x field))))

(defn do-action
  [s param]
  (case (:action param)
    :cut (cond
           (< 0 (count (:ch param))) (cut-char s (:ch param))
           (< 0 (:field param)) (cut-field s (:delim param) (:field param))
           :else nil)
    :grep 2
    nil))

(do-action "こんにち わーるど"
           {:action :cut
            :ch ""
            :field 1
            :delim #" "})

(do-action "こんにち わーるど"
           {:action :cut
            :ch "1,2,4"
            :field 0
            :delim #" "})