(ns clj-current-time.core
  (:require [clj-time.core :as t]
            [clj-time.local :as l]))

(defn greet
  ([]
   (greet (l/local-now)))
  ([dt]
   (let [h (t/hour dt)]
     (cond
       (<= 5  h 11) "おはようございます"
       (<= 12 h 17) "こんにちは"
       :else        "こんばんは") )))