如何使用全局变量初始化class属性？

Question

I'm using PHP 7.2.6

I know that "A variable declared outside a function has a GLOBAL SCOPE and can only be accessed outside a function".

I want to the already declared global variable into my class.

I want to initialize the class property using this global variable.

For it, I tried below code

<?php
$str = <<<EOD
Example of string
spanning multiple lines
using heredoc syntax.
EOD;

class foo
{
    var $foo;

    function __construct()
    {
        $this->foo = $str;
    }
}

$foo = new foo();
echo $foo->foo;
?>

I got following notice in my browser :

Notice: Undefined variable: str in hello.php on line 14

I'm not understanding why I'm getting this notice.

I'm not accessing the global variable $str inside any function. I'm using it inside a class.

Please help me in this regard and also explain me how should I use the global variable to initialize the class property?

Answer 1

To access a global variable you need to use the global variable with global keyword, Secondly your modifier and class shares the same name which afaik will confuse the compiler see the below snippet

Nope It doesn't

   <?php

$str = <<<EOD
Example of string
spanning multiple lines
using heredoc syntax.
EOD;

class foo
{
    public  $foo;

    function __construct()
    {
        global $str;
        $this->foo = $str;
    }


}

$foo = new foo();
echo $foo->foo;
?>

Snippet

Why not to use global variables