如何编写一个规格，其中一个地图有一个密钥基于另一个密钥具有异构内容

Question

我非常确定我需要一个多规格，它的工作原理。但我不确定如何说一个向量的关键值可以包含异构地图。

我的是我的源数据我想规格：

(def int-attr { :type "int" :validations [{ :min 0 } { :max 100 }] }) 
(def string-attr { :type "string" :validations [{ :presence true }] }) 

这是我有问题，这取决于type键validations键，"int"或"string"，我想在validations不同规格键。

我很确定我必须使用multi-spec。这是我曾尝试：

(defmulti attribute-type :type) 
(defmethod attribute-type "string" [a] ::string-validations) 
(defmethod attribute-type "int" [a] ::int-validations) 

;; how to say this is a vector of int-min-validation, or int-max-validation etc. 
;; (s/+ ...) and (s/or ...) maybe? 
(s/def ::int-validations (...) 
(s/def ::string-validations (...) 

;; not sure how to incorporate these...  
(s/def ::int-min-validation (s/keys :req-un [::min])) 
(s/def ::int-max-validation (s/keys :req-un [::max])) 
(s/def ::string-presence-validation (s/keys :req-un [::presence])) 

(s/def ::attribute (s/multi-spec attribute-type ::type)) 

(s/explain ::attribute int-attr) 
(s/explain ::attribute string-attr) 

Answer 1

我身边与你的问题有点玩过，我没有找到一个方法来对视::type的::validations键不同的规格。我其实不认为这是可能的。

我做了什么：

我定义int-validations和string-validations如下：所以

(defmulti attribute-type ::type) 

(defmethod attribute-type "int" [_] 
    (s/keys :req [::type ::int-validations])) 

(defmethod attribute-type "string" [_] 
    (s/keys :req [::type ::string-validations])) 

(s/def ::attribute (s/multi-spec attribute-type ::type)) 

(def int-attr { ::type "int" ::int-validations [{ :min 0 } { :max 100 }] }) 
(def string-attr { ::type "string" ::string-validations [{ :presence true }] }) 

(s/valid? ::attribute int-attr) ;; => true 

就像我说的，我不认为：

(s/def ::int-validations (s/cat :min (s/keys :req-un [::min]) 
           :max (s/keys :req-un [::max]))) 
(s/def ::string-validations (s/every (s/keys :req-un [::presence]) :count 1)) 

;; TESTING: 
(s/valid? ::int-validations [{ :min 0 } { :max 100 }]) ;; => true 
(s/valid? ::string-validations [{ :presence true }]) ;; => true 

然后我定义的multi-specattribute-type有一种方法可以在int-attr和中使用::validations密钥。这就是为什么我为他们定义了::int-validations和::string-validations。

也许我错了，不能基于类型有::validations不同的规格，如果是的话，我会很乐意找出它是可能的方式。

当然，您可以将::validations定义为(s/or ::int-validations ::string-validations)，但这并不能真正解决问题。

Answer 2

使用命名空间关键字允许相同的密钥，但符合规范使用两种不同的规格，即int/validations和string/validations值。要允许包含地图的矢量，一个不错的选择是使用s/coll-of。

(def int-attr { :type "int" :validations [{ :min 0 } { :max 100 }] }) 
(def string-attr { :type "string" :validations [{ :presence true }] }) 

(defmulti attribute-type :type) 
(defmethod attribute-type "string" [_] 
    (s/keys :req-un [::type :string/validations])) 
(defmethod attribute-type "int" [_] 
    (s/keys :req-un [::type :int/validations])) 

(s/def :int/validations (s/coll-of :int/validation)) 
(s/def :string/validations (s/coll-of :string/presence)) 

(s/def :int/validation (s/keys :opt-un [:int/min :int/max])) 
(s/def :int/min number?) 
(s/def :int/max number?) 
(s/def :string/presence (s/keys :req-un [::presence])) 

(s/def ::attribute (s/multi-spec attribute-type ::type)) 

(s/explain ::attribute int-attr) ;; => Success! 
(s/explain ::attribute string-attr) ;; => Success!