Need help with plugin layer

I am working on a cms, and have integrated a plugin layer based on Joomla 1.0. I have it working with my CMS... sorta.

Basically, I have set up two dummy plugins. One replaces {google} with an adsense block, and the other replaces {url} with the site url ( just dummy plugins ).

Now, it runs, but prints the content its replacing the tags in twice, once for each plugin. I have been messing with this script for awhile and just can't figure out how to get it to stop this duplication.

I have attached the plugin handler code, and a sample useage code. I did not provide the plugins, instead will paste a plugin sample below...

$opc->plugins->registerFunction('onAlterContent', 'googleReplacer');

/**
* Searches and replaces {google} in text
* @return Altered text
*/
function googleReplacer($content) 
{
	// Check to see if there is anything to replace first.  If nothing, simply return the text.
    if(strpos($content, '{google}' ) === false) 
	{
		return $content;
	} 
	else 
	{
		// The tag was found, now we must replace it with our google code
        $code = 'THIS WILL BE THE GOOGLE ADSENSE BLOCK';
        $content = str_replace('{google}', $code, $content);	
        return $content;
    }
}

Code (markup):

Just something basic to test the waters with. I am tired of manually adding these files and adding in the function, and really dont have too much time to sit down and write my own plugin handler ( if I even could ). Thanks for any help.

 

Sorry, Solved. I was returning the content in the plugin themselves rather than just returning true or simply, returning.