What are the functions of php traits?

The function of php traits is designed for single inheritance languages ​​​​such as php. It is designed to allow developers to easily share a series of methods between multiple classes in different inheritance systems to reduce the problems caused by single inheritance. limitations.

Traits is designed for single inheritance languages ​​like php. It is designed to allow developers to easily share a series of methods between multiple classes in different inheritance systems to reduce the limitations caused by single inheritance. The combination of traits and classes avoids a series of problems caused by multiple inheritance.

Using

First look at the example given in the official document:

<?php
trait ezcReflectionReturnInfo {
    function getReturnType() { /*1*/ }
    function getReturnDescription() { /*2*/ }
}
class ezcReflectionMethod extends ReflectionMethod {
    use ezcReflectionReturnInfo;
    /* ... */
}
class ezcReflectionFunction extends ReflectionFunction {
    use ezcReflectionReturnInfo;
    /* ... */
}
?>

As can be seen from the above example, the feature set ezcReflectionReturnInfo contains two Methods: getReturnType and getReturnDescription, and the following two subclasses inherit from different parent classes, but they can be reused by use ezcReflectionReturnInfo method. easy and convenient.

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Notes

• If there are methods with the same name in the traits of the subclass, parent class, and use, then the priority of these three methods is: subclass> tratis > parent class;

• You can use multiple traits at the same time, but you cannot use traits with the same name;

• If there is a method name conflict in multiple traits used, you can use to specify a method from a certain A trait. For example:

<?php
trait A {
    public function smallTalk() {
        echo &#39;a&#39;;
    }
    public function bigTalk() {
        echo &#39;A&#39;;
    }
}
trait B {
    public function smallTalk() {
        echo &#39;b&#39;;
    }
    public function bigTalk() {
        echo &#39;B&#39;;
    }
}
class Talker {
    use A, B {
        B::smallTalk insteadof A;
        A::bigTalk insteadof B;
    }
}

• The method can use as to set the alias, but it is only valid in this class.

class Aliased_Talker {
    use A, B {
        B::smallTalk insteadof A;
        A::bigTalk insteadof B;
        B::bigTalk as talk;
    }
}

• When using as, you can also change the visibility of the method.

class MyClass2 {
    use HelloWorld { sayHello as private myPrivateHello; }
}

• traits can be nested, for example, A can use B.

<?php
trait Hello {
    public function sayHello() {
        echo &#39;Hello &#39;;
    }
}
trait World {
    public function sayWorld() {
        echo &#39;World!&#39;;
    }
}
trait HelloWorld {
    use Hello, World;
}

• Traits can define abstract methods. Similarly, the class that uses the traits also needs to implement these abstract methods;

• Conventional variables, static variables and methods can be defined in traits;

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