Question

我在下面创建了参考“ people”，并希望函数delete-person从事务内的数据结构中删除项目。

(defrecord Person [name favorite-color])

(def people (ref ()))

(defn add-person [new-person]
  (dosync
    (alter people conj new-person)))

(add-person (Person. "Joe" "Red"))
(add-person (Person. "Sam" "Blue"))

;; how do I make this function work? 
;; would @people (destructured) have to be the second argument to filter? 
(defn delete-person [name-to-delete]
  "Delete named person from ref"
  (dosync
    (alter people filter #(not= (:name %) name-to-delete))))

(delete-person "Joe")

IllegalArgumentException Don't know how to create ISeq from: 
user$delete_person$fn__1407$fn__1408  clojure.lang.RT.seqFrom (RT.java:542)

下面的函数起作用是因为我过滤了非结构化的ref，但是如何在事务中更改数据呢？

   (filter #(not= (:name %) "Sam") @people)
=> (#user.Person{:name "Joe", :favorite-color "Red"})

Clojure：要从裁判中删除项目吗？

0 个答案: