An article to talk about the new features Traits of php5.4

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

<?php
class Base {
    public function sayHello() {
        echo &#39;Hello &#39;;
    }
}

trait SayWorld {
    public function sayHello() {
        parent::sayHello();
        echo "World!\n";
    }
}

class MyHelloWorld extends Base {
    use SayWorld;
}

class MyHelloWorldExt extends Base {
	use SayWorld;
	public function sayHello() {
        /**
		 * 这里是5.4中的新的改动，5.4之前的版本会提示:
		 * PHP Fatal error:  Cannot use string offset as an array
		 * 5.4中改进为返回字符串中的该索引号的字符
		 */
		$str  = "Arvin";
		echo $str[0][0];// echo &#39;A&#39;;
    }

	public function shortArray() {
		$array = [&#39;first&#39;, 2, 3, 4];//5.4中的数组简单语法
		echo $array[0];//5.4中的数组解引用取数组元素方法
	}
}

$o = new MyHelloWorld();
$o->sayHello();
$oe = new MyHelloWorldExt();
$oe->sayHello();
echo "\n";
$oe->shortArray();

Hello World!
A
first

<?php
trait Hello {
    public function sayHello() {
        echo &#39;Hello &#39;;
    }
}

trait World {
    public function sayWorld() {
        echo &#39;World&#39;;
    }
}

class MyHelloWorld {
    use Hello, World;
}

$o = new MyHelloWorld();
$o->sayHello();
$o->sayWorld();
?>

Hello World

<?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;
}
}

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

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

// Change visibility of sayHello，改变sayHello的访问权限。
class MyClass1 {
use HelloWorld { sayHello as protected; }
}

// Alias method with changed visibility
// sayHello visibility not changed，设置别名myPrivateHello。
class MyClass2 {
use HelloWorld { sayHello as private myPrivateHello; }
}
?>

<?php
trait Hello {
public function sayHello() {
echo &#39;Hello &#39;;
}
}

trait World {
public function sayWorld() {
echo &#39;World!&#39;;
}
}

trait HelloWorld {
use Hello, World;
}

class MyHelloWorld {
use HelloWorld;
}

$o = new MyHelloWorld();
$o->sayHello();
$o->sayWorld();
?>

Hello World!

<?php
trait Hello {
    public function sayHelloWorld() {
        echo &#39;Hello &#39;.$this->getWorld();
    }
    abstract public function getWorld();
}

class MyHelloWorld {
    private $world;
    use Hello;
	public function __construct($world) {
		$this->world = $world;
	}
    public function getWorld() {
        return $this->world;
    }
}

/**
 * 这里用到了5.4新功能 类实例化解引用操作
 * (new class())->method();
 */
(new MyHelloWorld(&#39;Arvin&#39;))->sayHelloWorld();
?>

Hello Arvin

<?php
trait Counter {
    public function inc() {
        static $c = 0;//静态变量
        $c += 1;
        echo "$c\n";
    }
	/**
	 * 静态方法
	 */
	public static function doSomething() {
        echo &#39;Doing something&#39;;
    }
}

class C1 {
    use Counter;
}

(new C1())->inc(); // echo 1
C1::doSomething();
?>
输出为：
1
Doing something

<?php
trait PropertiesTrait {
    public $x = 1;
	public $y = 2;
}

class PropertiesExample {
    use PropertiesTrait;
	public $x = 1;
	//public $y = 3;
}

$example = new PropertiesExample;
echo $example->x, $example->y;
?>

12

Added short array syntax support ([1,2,3]), see UPGRADING guide for full details.
Added binary numbers format (0b001010).
Added support for Class::{expr}() syntax.
Added support for Traits.//本文的主要内容
Added closure $this support back.
Added array dereferencing support.//数组解引用支持,上文中有实例
Added callable typehint.
Added indirect method call through array. #47160.
Added DTrace support.//传说DTrace是一个性能分析工具,可以跟踪出函数调用点,返回点等数据
Added class member access on instantiation (e.g. (new foo)->bar()) support.//类新实例解引用操作,上文中有实例