1
让我们看看在Clojure的规格Guide给出的例子为clojure.spec/merge
发生器的两套钥匙的联盟使用Clojure规格命名参数
(require '[clojure.spec :as spec]
'[clojure.spec.gen :as gen])
(spec/def :animal/kind string?)
(spec/def :animal/says string?)
(spec/def :animal/common (spec/keys :req [:animal/kind :animal/says]))
(spec/def :dog/tail? boolean?)
(spec/def :dog/breed string?)
(spec/def :animal/dog (spec/merge :animal/common
(spec/keys :req [:dog/tail? :dog/breed])))
从这个规范我们都可以产生数据,进而对其进行验证:
(gen/generate (spec/gen :animal/dog))
=> {:animal/kind "bB", :animal/says "z9C0T465Q8OPXn5dUB8Wqk8K5Jnn",
:dog/tail? false, :dog/breed "B2MLQnj"}
(spec/valid? :animal/dog
{:animal/kind "bB", :animal/says "z9C0T465Q8OPXn5dUB8Wqk8K5Jnn",
:dog/tail? false, :dog/breed "B2MLQnj"})
=> true
但是,如果我们稍微修改的规范,这样,这是对的命名参数而不是地图的序列,像
(spec/def :animal/common (spec/keys* :req [:animal/kind :animal/says]))
(spec/def :animal/dog (spec/merge :animal/common
(spec/keys* :req [:dog/tail? :dog/breed])))
,我们仍然可以验证数据,对规范:
(spec/valid? :animal/dog
'(:animal/kind "dog"
:animal/says "woof"
:dog/tail? true
:dog/breed "retriever"))
=> true
但我们确实失去了产生数据的能力:
(gen/generate (spec/gen :animal/dog))
; 1. Unhandled clojure.lang.ExceptionInfo
; Couldn't satisfy such-that predicate after 100 tries.
这是站在我这边的错误,在规范的执行错误,或只是clojure.spec/merge
的意图工作的方式?我们可以通过附加发生器来解决这个问题吗?