Clojure Spec中`&`和`和`有什么区别？

Question

我似乎很难分清Clojure Spec &和and运算符的含义.他们似乎都做了同样的事情,只有一个被注意为正则表达式运算符,差异我不确定我理解它的重要性.

Answer 1

如果我们从它们中采样一些数据,我们可以看到两者之间的差异:

(ns playground
  (:require [clojure.spec     :as spec]
            [clojure.spec.gen :as gen]))

(gen/generate (spec/gen (spec/and #{:a :c} #{:b :a :c})))
=> :a
(gen/sample (spec/gen (spec/and #{:a :c} #{:b :a :c})))
=> (:c :a :c :a :a :a :a :a :a :c)

正如我们所看到的spec/and匹配单个出现的匹配两个谓词#{:a :c}和#{:b :a :c}.

(gen/generate (spec/gen (spec/& #{:a :c} #{:b :a :c})))
=> [:c]
(gen/sample (spec/gen (spec/& #{:a :c} #{:b :a :c})))
=> ([:c] [:a] [:a] [:c] [:c] [:c] [:c] [:a] [:c] [:c])

spec/&另一方面,匹配谓词作为序列的一部分接受的内容.