PHP code style

If you use a third-party framework and provide code style instructions, follow its code style standards, otherwise as follows!

== Format:

* Use UTF-8 encoding

* Use 4 spaces for indentation, tabs are prohibited

* Unix style line breaks (LF)

* Used by comma, colon and semicolon operators Spaces

* Do not use spaces before (, [ after, ],)

* Use 4 spaces for indentation in code blocks

* Use hierarchical indentation

* Use a blank line before the return value of the return method (Unless there is only one line of code) and use blank lines to distinguish between two methods

* Use blank lines to distinguish between two large logical code segments

* Keep the number of lines within 80 words, no more than 120

* Use standard PHP tag delimitation, prohibit the use of short tags ( //... ?>), and prohibit the use of PHP end tags ("?>") for files that only contain PHP code
, use the comment "/* End of file */" at the end of the file

* A single line of code must also end with a semicolon (;)

== Naming:

* The file name uses snake_case. It is forbidden to use bloated file names

* Use snake_case method for variable names, and it is forbidden to use bloated variable names
* It is forbidden to use single characters as local variables (such as $i), except in for loops
* It is forbidden to use uppercase letters as Global variables, if capital letters are used, should use SCREAMING_SNAKE_CASE

* Use CamelCase for class names, and camelCase for method names (keep capitalization of abbreviations like HTTP, RFC, XML)

* Use SCREAMING_SNAKE_CASE for constant names

// bad
superclass.php
SuperClass.php
superClass.php
$i = "foobar";  // 单字符变量只充许使用在for循环中
$bufferdText   // 驼峰式变量，并且意思可以再精简些
$groupid        // 两个单词之间需要下划线分开
$name_of_last_city_used // 太长
MyConstant       // 应该用下划线并且字母没有全大写
N                     // 单字符
S_C_VER           // 意思不清楚
class superclass
class superClass
function fileproperties() // 意思不清楚并且没有驼峰式命名
function fileProperties() // 意思不清楚
function getfileproperties() // 好些了，但没有驼峰式命名
// good
super_class.php
for ($i = 0; $i < 10; $i++)
$buffer
$group_id
$last_city
MY_CONSTANT
NEWLINE
SUPER_CLASS_VERSION
class SuperClass
function getFileProperties()

== Syntax:

For PHP code embedded in HTML, for code blocks like if, for, foreach, while, etc., use if: ... endif; for: ... endfor; foreach: ... endforeach; and while: ... endwhile; method block

...
<?php if ($user->isLoggedIn()): // checking logged in ?>
<!-- HTML goes here. -->
<?php endif; // end checking logged in ?>
<?php foreach ($users as $user): // loop users ?>
<!-- HTML goes here. -->
<?php endforeach; // end loop users ?>
...

== Note:

* Document block must be compatible with phpDocumentor format, please refer to: http://phpdoc.org/

* Avoid redundant comments

/**
 * 控制器类说明信息
 */
class Controller {
    private static $instance;
    public function __construct()  {
        ...
    }
    /**
     * 函数说明信息
     */
    public static function &get_instance() {
        ...
    }
/* End of file controller.php */