PHP 4 compatible plugin engine

admin/options.php

 											<option value="0" <?php if(!$conf->check_version) echo "selected=\"selected\""; ?>><?php echo __("Deactive")?></option>
 										</select>
 									</li>
-<?php	print_r($trigger);echo "<br>";die("Antes de trigger->call add options panel");
-									$trigger->call('add_options_panel');	
+<?php
+									$trigger->call('add_options_panel');									
 ?>									
 								</ul>
 							</fieldset>

classes/plugin.class.php

   =========================== */
 ?>
 <?php
-	class plugin {	
+	class plugin {
 		
 		var $actions = array();
 		var $exists = array();
 	
-		function call($name) {            
-
+		function call($name) {			
+			
 			if (!$this->exists($name)) {
 				return false;
-			}            
-
- 			/*echo "<br />==========<br />";
-			echo $name;
-			echo "<br />";*/
+			} 			
 			
 			$index = 0;
-			//foreach (plugins::$instances as $plugin) {
+			
 			foreach ($GLOBALS['plugins::$instances'] as $plugin) {
 				if(array_key_exists($index,$this->actions[$name])){
 					$action = $this->actions[$name][$index][1]; 
-					if (is_callable(array($plugin, $action))) {
-						//echo "ejecutar: ".$action."()<br/>";					
+					if (is_callable(array($plugin, $action))) {						
 						$plugin->$action();
 						$index++;
 					}
 		function exists($name) {
             if (isset($this->exists[$name])) {
                 return $this->exists[$name];
-			}
-
-            //foreach (plugins::$instances as $plugin) {
-			foreach ($GLOBALS['plugins::$instances'] as $plugin) {
-				/*print_r(plugins::$instances);
-				echo "<br />";
-				print_r($plugin);
-				echo "<br />";
-				print_r($this->actions[$name]);
-				echo "<br />";
-				echo $this->actions[$name][0][1];
-				echo "<br />";*/
+			}			
+            
+			foreach ($GLOBALS['plugins::$instances'] as $plugin) {				
 				if(array_key_exists($name,$this->actions)){
 					if (is_callable(array($plugin, $this->actions[$name][0][1]))) {
 						return $this->exists[$name] = true;
 
             return $this->exists[$name] = false;
         }		
-        
-		function instance(){
-			//$instance;			
-			if( !isset($GLOBALS['$instance']) ) {
-				$GLOBALS['$instance'] = new plugin();
+		
+		//I really hate you PHP4's OOP implementation
+		function &instance() {
+			static $instance;
+			if (!isset($instance)) {
+				$instance = new plugin();
 			}
-			//print_r($GLOBALS['$instance']);
-			//die();
-			return $GLOBALS['$instance'];
-        }
+			return $instance;   
+		}
 		
 	}
 ?>

classes/plugins.class.php

   =========================== */
 ?>
 <?php
-	$GLOBALS['plugins::$instances'] = array(); /* class static property */
-	class plugins {		
+	/* Simulating a class static property */
+	$GLOBALS['plugins::$instances'] = array();
+	
+	class plugins {
 		
-		function addAction($name, $function) {
-	    	$plugEngine = plugin::instance();
-	    	$plugEngine->actions[$name][] = array($this, $function);	    	
+		function addAction($name, $function) {	    	
+			$plugEngine =& plugin::instance(); //DO NOT remove the & after the =
+	    	$plugEngine->actions[$name][] = array($this, $function);
 	    }
 		
 	}

classes/util.class.php

         
 		$actives = json_decode($conf->active_plugins,1);
 		$actives = $actives[1];
+		
         foreach ($actives as $index => $plugin) {
             if (!file_exists(Absolute_Path."plugins/".$plugin)) {
                 unset($actives[$index]);
                 continue;
-            }else{
+            } else {
 				require_once(Absolute_Path.'plugins/'.$plugin);
 			}            
 			if (!class_exists($index)) {
                 continue;
 			}
-			//plugins::$instances[$index] = new $index;
 			$GLOBALS['plugins::$instances'][$index] = new $index;
         }
 	}

entry.php

 ob_start();
 if(!defined('entry') || !entry) die('Not a valid page');
 
-
 error_reporting (E_ALL);
 ini_set('display_errors', '1');
 
 // PHP settings specific to Gelato
 ini_set('pcre.backtrack_limit', '10000');
-// Globals to be used throughout the application
+
 define('Absolute_Path', dirname(__FILE__).DIRECTORY_SEPARATOR);
 $installed = true;
 $configFile = Absolute_Path.'config.php';
 
 require_once(Absolute_Path.'classes'.DIRECTORY_SEPARATOR.'configuration.class.php');
 require_once(Absolute_Path.'classes'.DIRECTORY_SEPARATOR.'util.class.php');
-//require_once(Absolute_Path.'classes'.DIRECTORY_SEPARATOR.'functions.php');
 require_once(Absolute_Path.'classes'.DIRECTORY_SEPARATOR.'gelato.class.php');
 require_once(Absolute_Path.'classes'.DIRECTORY_SEPARATOR.'templates.class.php');
 require_once(Absolute_Path.'classes'.DIRECTORY_SEPARATOR.'themes.class.php');
 	session_start();
 	
 	util::init_plugins();
-	$trigger = plugin::instance();
+	$trigger =& plugin::instance(); //DO NOT remove the & after the =	
 	
 	$trigger->call('gelato_init');