An article to talk about the features of php5.4 [Summary]

This article will talk about the features of php5.4 (Short Open Tag, array abbreviation form, Traits, etc.). If you need it, you can take a look. I hope it will be helpful to everyone!

Short Open Tag

Short Open Tag is always available since PHP5.4.
Here we will focus on the issues related to PHP start and end tags. That is:

<?php
// Code...
?>

is usually the above form. In addition, there is also an abbreviated form:

<? /* Code... */ ?>

You can also put <em><?php echo $ xxoo;?></em>

is abbreviated as: <em><?= $xxoo;?></em>

This kind The abbreviated form is called Short Open Tag, which is enabled by default in PHP5.3 and always available in PHP5.4.

Using this shorthand form will be very convenient for embedding PHP variables in HTML.

For pure PHP files (such as class implementation files), PHP officially recommends writing the start tag in the top format and omitting the end tag.

This ensures that the entire PHP file is PHP code without any output, otherwise you will encounter some trouble when setting the Header and Cookie after including the file [Note].

Note :Header and Cookie must be sent before any content is output.

Array abbreviation

This is a very convenient feature!

The code is as follows:

// 原来的数组写法
$arr = array("key" => "value", "key2" => "value2");
// 简写形式
$arr = ["key" => "value", "key2" => "value2"];

Traits

// Traits不能被单独实例化，只能被类所包含
trait SayWorld
{
    public function sayHello()
    {
        echo 'World!';
    }
}
class MyHelloWorld
{
    // 将SayWorld中的成员包含进来
    use SayWorld;
}
$xxoo = new MyHelloWorld();
// sayHello() 函数是来自 SayWorld 构件的
$xxoo->sayHello();

Traits can also include Traits. The space is limited and I cannot give examples one by one.

Built-in Web server

It is indeed very convenient to use it in the development environment.

php -S localhost:8000

Where localhost is the listening ip, 8000 is the listening port, which can be modified by yourself.

php -S localhost:8000 index.php

Details modification

$func = "funcXXOO";
A::{$func}();

(new MyClass)->xxoo();

print func()[0];

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