PHP global event handling in a single function.

event.function.php

<?php

/*
 *  Use
 *     event('eventname',function(){ ... })
 *  to add an event handler for 'eventname' event.
 *
 *  Trigger an event with
 *     event('eventname')
 *
 *  You can also pass parameters to handlers triggering the event 
 *  passing an array as the second parameter:
 *     event('eventname',[1,2,3])
 *     
 */ 

function event($name,$cb = null){
	static $e = array();
	if ( is_callable($cb) ){
		empty( $e[$name] ) ? $e[$name] = array($cb) : $e[$name][] = $cb;
	} elseif ( false === empty($e[$name]) ) {
		$a = is_array($cb) ? $cb : array();
		foreach ($e[$name] as $eh) call_user_func_array($eh,$a);
	}
}

example.php

<?php

// Example :
// http://3v4l.org/tS5Sd

// Add a foo event handler
event('foo',function(){
	print_r(func_get_args());
});

// Add another foo event handler
event('foo',function(){
	echo 'Hello, friend!';
});


// Call foo event with parameters
event('foo',[1,2]);

// Call bar event (does nothing)
event('bar');