[TUT] Using the Singleton Pattern

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Using the singleton pattern is drop-dead easy. I'll guild you through it...

Make a PHP file and define a class and static function and variable... Like this...

<?php
class singleton
{
   # static so we don't need to make an instance of this
   private static $instances = array();

   # static so we don't need to make an instance of this
   public static function instance($class)
   {
   }
}

Now, to put our business in the function:

class singleton
{
   # static so we don't need to make an instance of this
   private static $instances = array();

   # static so we don't need to make an instance of this
   public static function instance($class)
   {
      if(!isset(self::$instances[$class])) # does the class already exist?
         self::$instances[$class] = new $class; # new class

      return self::$instances[$class]; # return it!
   }
} 

How easy was THAT!?

What are the advantages of using this?
Well, it limits the number of instances of the class there is. Like if you have a query on your __construct function, then you'd need singleton so that PHP doesn't 'lag' and make more instances than there should be, therefore running the query too much.
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I hope you guys still aren't using globals! (berk RadiPanel)