PHP 8.2 新特性之 DNF Types
hi,我是温新,一名 PHPer
PHP 8.2 引入一个新的类型叫 DNF(Disjunctive Normal Form)。这个类型是 |
和 &
运算符的组合。它允许指定一种类型是两个或多个类型的联合,而每个类型是一个或多个其他类型的交集。
这样说挺不容易理解的,先通过 demo 演示,后续再来解释吧。
<span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(86, 182, 194) !important"><?</span><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">php</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box"></span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">interface</span> <span style="box-sizing: border-box;color: rgb(224, 108, 117) !important">User</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">{</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">public</span> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">function</span> <span style="box-sizing: border-box;color: rgb(224, 108, 117) !important">getName</span>(): <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">string</span>;</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">}</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box"></span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">interface</span> <span style="box-sizing: border-box;color: rgb(224, 108, 117) !important">Admin</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">{</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">public</span> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">function</span> <span style="box-sizing: border-box;color: rgb(224, 108, 117) !important">getName</span>(): <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">string</span>;</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">}</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box"></span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">interface</span> <span style="box-sizing: border-box;color: rgb(224, 108, 117) !important">SuperAdmin</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">{</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">public</span> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">function</span> <span style="box-sizing: border-box;color: rgb(224, 108, 117) !important">getName</span>(): <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">string</span>;</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">}</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box"></span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box"></span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(98, 151, 85) !important">// PHP 7 特性,匿名类</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(224, 108, 117) !important">$user</span> <span style="box-sizing: border-box;color: rgb(86, 182, 194) !important">=</span> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">new</span> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">class</span> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">implements</span> <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">Admin</span>, <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">SuperAdmin</span> {</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">public</span> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">function</span> <span style="box-sizing: border-box;color: rgb(224, 108, 117) !important">getName</span>(): <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">string</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"> {</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">return</span> <span style="box-sizing: border-box;color: rgb(152, 195, 121) !important">'PHP 8.2 DNF'</span>;</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"> }</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">};</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box"></span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(98, 151, 85) !important">// 这是重点,看参数,接收的参数含义是:</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(98, 151, 85) !important">// 该函数接收一个 同时实现了 Admin 和 SpuerAdmin 接口的 User 对象实例</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">function</span> <span style="box-sizing: border-box;color: rgb(224, 108, 117) !important">get_user_name</span>((<span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">Admin</span> <span style="box-sizing: border-box;color: rgb(86, 182, 194) !important">&</span> <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">SuperAdmin</span>) <span style="box-sizing: border-box;color: rgb(86, 182, 194) !important">|</span> <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">User</span> <span style="box-sizing: border-box;color: rgb(224, 108, 117) !important">$user</span>): <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">string</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">{</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">return</span> <span style="box-sizing: border-box;color: rgb(224, 108, 117) !important">$user</span><span style="box-sizing: border-box;color: rgb(86, 182, 194) !important">-></span><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">getName</span>();</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">}</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box"></span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">echo</span> <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">get_user_name</span>(<span style="box-sizing: border-box;color: rgb(224, 108, 117) !important">$user</span>); <span style="box-sizing: border-box;color: rgb(98, 151, 85) !important">// 输出:PHP 8.2 DNF</span></span>
代码解释:
- 1、定义了三个接口,User、Admin、SuperAdmin;
- 2、定义一个匿名类,并实现 Admin、SuperAdmin 接口;
- 3、定义一个函数,该参数使用 dnf 类对参数进行限制,只允许接收同时实现了 Admin 和 SuperAdmin 接口的实例对象调用,否则报错;
- 4、调用函数。
下面将针对几种情况进行演示。
DNF 正确的使用方法
-
A|B|C
-
A|B|(C&D)
-
(A&B&C)|null
使用 & 时,必须使用
()
进行包裹。
A|B|C 用法
A B C 三个接口只要实现其中一个即可
<span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(98, 151, 85) !important">// 该匿名名实现了 User 接口</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(224, 108, 117) !important">$user</span> <span style="box-sizing: border-box;color: rgb(86, 182, 194) !important">=</span> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">new</span> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">class</span> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">implements</span> <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">User</span> {</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">public</span> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">function</span> <span style="box-sizing: border-box;color: rgb(224, 108, 117) !important">getName</span>(): <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">string</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"> {</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">return</span> <span style="box-sizing: border-box;color: rgb(152, 195, 121) !important">'PHP 8.2 DNF'</span>;</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"> }</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">};</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box"></span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(98, 151, 85) !important">// A|B|C 只要有一个实现了即可,否则会报错</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">function</span> <span style="box-sizing: border-box;color: rgb(224, 108, 117) !important">get_user_name</span>(<span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">Admin</span> <span style="box-sizing: border-box;color: rgb(86, 182, 194) !important">|</span> <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">SuperAdmin</span> <span style="box-sizing: border-box;color: rgb(86, 182, 194) !important">|</span> <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">User</span> <span style="box-sizing: border-box;color: rgb(224, 108, 117) !important">$user</span>): <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">string</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">{</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">return</span> <span style="box-sizing: border-box;color: rgb(224, 108, 117) !important">$user</span><span style="box-sizing: border-box;color: rgb(86, 182, 194) !important">-></span><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">getName</span>();</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">}</span>
(A&B)|C
实例对象 C 必须实现 A、B两个接口。本案例中 $user
实例对象必须实现 Admin
、SuperAdmin
接口。
<span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(224, 108, 117) !important">$user</span> <span style="box-sizing: border-box;color: rgb(86, 182, 194) !important">=</span> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">new</span> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">class</span> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">implements</span> <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">Admin</span>, <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">SuperAdmin</span>{</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">public</span> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">function</span> <span style="box-sizing: border-box;color: rgb(224, 108, 117) !important">getName</span>(): <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">string</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"> {</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">return</span> <span style="box-sizing: border-box;color: rgb(152, 195, 121) !important">'PHP 8.2 DNF'</span>;</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"> }</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">};</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box"></span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"><span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">function</span> <span style="box-sizing: border-box;color: rgb(224, 108, 117) !important">get_user_name</span>((<span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">Admin</span> <span style="box-sizing: border-box;color: rgb(86, 182, 194) !important">&</span> <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">SuperAdmin</span>) <span style="box-sizing: border-box;color: rgb(86, 182, 194) !important">|</span> <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">User</span> <span style="box-sizing: border-box;color: rgb(224, 108, 117) !important">$user</span>): <span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">string</span></span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">{</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px"> <span style="box-sizing: border-box;color: rgb(198, 120, 221) !important">return</span> <span style="box-sizing: border-box;color: rgb(224, 108, 117) !important">$user</span><span style="box-sizing: border-box;color: rgb(86, 182, 194) !important">-></span><span style="box-sizing: border-box;color: rgb(209, 154, 102) !important">getName</span>();</span><br></br><span style="box-sizing: border-box;color: rgb(171, 178, 191);padding-right: 0.1px">}</span>
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