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

##The so-called Traits are "components", which are used to replace inheritance. mechanism. Multiple inheritance is not possible in PHP, but a class can contain multiple 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 also have many magical functions, such as containing multiple Traits, resolving conflicts, modifying access permissions, setting aliases for functions, etc. .

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

Built-in Web server

PHP has a built-in one starting from 5.4 A lightweight web server that does not support concurrency and is positioned for development and debugging environments.

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

php -S localhost:8000

This creates a Web server in the current directory, which you can access through http://localhost:8000/.

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

In many applications, URL rewriting is performed, so PHP provides a function to set routing scripts:

php -S localhost:8000 index.php

In this way, all requests will be processed by index.php.

You can also use XDebug for breakpoint debugging.

Details modification

PHP5.4 adds a new way to dynamically access static methods:

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

Added in the instance Characteristics of accessing class members when changing:

(new MyClass)->xxoo();

Added support for member access analysis of function return arrays (this writing method will report an error in previous versions):

print func()[0];

Recommended study: "

PHP video tutorial》

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