为什么这个函数不在包含时执行？

Question

I am including a PHP file and that file should, I think, execute a function when included but it isn't. Can you fill me in why its not executing and how I can make it execute?

<?php
// editor.php

if (class_exists('Editor'))
    return;

class Editor {
  public static function initialise() {
    // do some initialisation ...
  }
}

Editor::initialise(); // this function doesn't appear to execute
// Alternate approach: which also doesn't seem to execute
function editor_init() {
    Editor::initialise(); 
}
editor_init();

Usage:

// Usage
<?php
// main.php

require_once('editor.php'); // here I expect my initialise() function be executed but it isn't.
// Alternate approach
include_once('editor.php'); // here I expect my initialise() function be executed but it isn't.
// Alternate approach
include('editor.php'); // here I expect my initialise() function be executed but it isn't.

Answer 1

The reason is you are calling if (class_exists('Editor')) which returns true .

Your main.php file should look like:

// main.php

if (class_exists('Editor')):
    return;
else:
    require_once('editor.php'); // here I expect my initialise() function be executed but it isn't.
endif;

And your editor.php file should look like:

// editor.php

class Editor {
  public static function initialise() {
    // do some initialisation ...
    echo 'Yes, I am being called.';
  }
}

Editor::initialise();