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POCan PHP Perform Magic Instantiation?
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copied!<p>Given a class <code>class RandomName extends CommonAppBase {}</code> is there any way to automatically create an instance of any class extending <code>CommonAppBase</code> without explicitly using <code>new</code>?</p> <p>As a rule there will only be one class definition per PHP file. And appending <code>new RandomName()</code> to the end of all files is something I would like to eliminate. The extending class has no constructor; only <code>CommonAppBase</code>'s constructor is called. <code>CommonAppBase->__construct()</code> kickstarts the rest of the apps execution.</p> <p>Strange question, but would be nice if anyone knows a solution.</p> <h2>Edit</h2> <p>Further to the below comment. The code that does the instantiation won't be in the class file. The class file will be just that, I want some other code to <code>include('random.class.php')</code> and instantiate whatever class extending <code>CommonAppBase</code> is in there.</p> <p>For anyone unsure what I am after <a href="https://stackoverflow.com/questions/2813413/can-php-perform-magic-instantiation/2813734#2813734">my hackish answer</a> does what I want, but not in the sanest way.</p> <p>Thanks in advance, Aiden</p> <p>(btw, my PHP version is 5.3.2) Please state version restrictions with any answer.</p> <h2>Answers</h2> <p>The following can all be appended to a file (through php.ini or with Apache) to auto launch a class of a specific parent class.</p> <p>First (thanks dnagirl)</p> <pre><code>$ca = get_declared_classes(); foreach($ca as $c){ if(is_subclass_of($c, 'MyBaseClass')){ $inst = new $c(); } } </code></pre> <p>and (the accepted answer, as closest answer)</p> <pre><code>auto_loader(); function auto_loader() { // Get classes with parent MyBaseClass $classes = array_filter(get_declared_classes(), function($class){ return get_parent_class($class) === 'MyBaseClass'; }); // Instantiate the first one if (isset($classes[0])) { $inst = new $classes[0]; } } </code></pre>

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