clojure - 通过 recur 调用时 conj 不添加到向量末尾

Question

为什么这一直问 jack 是否想要一杯茶而不是其他父亲。

(defn tea-anyone
  "Ask 'fathers' if they would like some tea"
  [fathers]
  (loop [asks 0 to-ask fathers]
    (let [[father & others] to-ask]
      (println (str "Cup of tea " father "? "))
        (if (> asks 6)
          (println (str father ": All right then!"))
          (recur (inc asks) (conj others father))))))

(tea-anyone ["Jack" "Ted" "Dougle"])

Answer 1

因为 others 不是向量。亲自看看:

(let [[f & o :as a] [1 2 3 4]]
    (println f)
    (println o)
    (println a)
    (println (type f))
    (println (type o))
    (println (type a))
    (println (type (conj o 5)))
    (println (type (conj a 5))))

要达到您想要的效果，您可以使用 cycle .