Can a certain class be expanded globally in php?

The project I am working on is full of statements like global $app;. Is there any way to use $app directly without global $app;?

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The project I am working on is full of statements like global $app;. Is there any way to use $app directly without global $app;?

Regardless of OOP, variables outside functions in PHP are global variables.
To use global variables within a function, you need to use global declarations. Of course, you can also consider passing parameters.
PHP itself provides many "super" Global variables such as $_SERVER/$_COOKIE, etc. do not require a global declaration.
Windows registry appears to PHPer as a $win = array();Hash table (multi-dimensional array) in the global scope, which can store various Configuration information of various applications and modules. Why does PHP web application exclude such an application-level global array? Like Discuz!, there is such a global array named $_G[].

Of course, some people are uncomfortable with OOP and just don’t like global arrays, so that’s fine:

<code><?php
class App {
    private static $options = array(
        'db_host' => '127.0.0.1',
        'db_user' => 'yaber',
        'db_pass' => '123456',
        'db_name' => 'yabase',
        'db_port' => 3306
    );
    public static function config($key = '') {
        return ($key == '') ? self::$options : self::$options[$key];
    }
}
function bar() {
    echo App::config('db_name');
}
bar(); //输出 yabase</code>

The biggest advantage of static methods of a class is that the class can be directly used without instantiation, but it cannot access the non-static member variables and methods of the class.