Question

I m trying to call clojure.walk/stringify-keys on a map that might include record instances. Since stringify-keys is recursive, it attempts to convert the keys on my record, (since (map? record-var) is true) which causes an error. Is there any way to tell if a var is a record rather than just a Clojure map? I d like to provide my own implementation of stringify-keys that is record-aware.

现有<条码>星号的实施原因如下:

(use  [clojure.walk :only [stringify-keys]])

(defrecord Rec [x])    

(let [record (Rec. "foo")
      params {:x "x" :rec record}]
    (stringify-keys params))

造成以下例外: 未支持的行动例外 Can t 造成空洞:用户。接收用户。收入(单位:千美元)

Answer 1

记录似乎采用了“记录标记”接口:

user=> (defrecord Rec [x])    
user.Rec

user=> (require  [clojure.reflect :as r])
nil
user=> (:bases (r/reflect Rec))
#{java.io.Serializable clojure.lang.IKeywordLookup clojure.lang.IPersistentMap clojure.lang.IRecord java.lang.Object clojure.lang.IObj clojure.lang.ILookup java.util.Map}

user=> (instance? clojure.lang.IRecord (Rec. "hi"))
true

Update 1.6 now has the record? functions

Answer 2

你可以检查每个成员的类型,看看它是否真的是一个地图或其他东西(如果其他东西被推定为记录)。

user> (type {:a 1 :b 2})
clojure.lang.PersistentArrayMap

友情链接