/**
     * Simple function to send an email
     * 
     * @param string $to
     * @param string $from
     * @param string $subject
     * @param string $body
     * @param string $extra_header
     * @return boolean
     */
    function email($to,$from,$subject,$body,$headers=NULL)
    {
        //we add hook just in case we want to overwrite the email function
        //example    Hook::add_action('email','some_function_used_instead_email');
        if (Hook::exists_action('email'))
        {
            return Hook::do_action('email',func_get_args());
        }
        else 
        {
            if ($headers==NULL)
            {
                $headers = 'MIME-Version: 1.0' . PHP_EOL;
                $headers.= 'Content-type: text/html; charset=utf8'. PHP_EOL;
                $headers.= 'From: '.$from.PHP_EOL;
                $headers.= 'Reply-To: '.$from.PHP_EOL;
                $headers.= 'Return-Path: '.$from.PHP_EOL;
                $headers.= 'X-Mailer: PHP/' . phpversion().PHP_EOL;
            }
 
            return mail($to,$subject,$body,$headers);
        }
    }

//Adding action to a hoook:
Hook::add_action('unique_name_hook','some_class::hook_test');
//OR shortcut:
add_action('unique_name_hook','other_class::hello');
add_action('unique_name_hook','some_public_function');
 
//Performing all the actions for the hook
do_action('unique_name_hook');//you can use too Hook::do_action();

class Hook
{
    //action hooks array   
    private static $actions = array();
 
    /**
     * ads a function to an action hook
     * @param $hook
     * @param $function
     */
    public static function add_action($hook,$function)
    {    
        $hook=mb_strtolower($hook,CHARSET);
        // create an array of function handlers if it doesn't already exist
        if(!self::exists_action($hook))
        {
            self::$actions[$hook] = array(); 
        }
 
        // append the current function to the list of function handlers
        if (is_callable($function))
        {
            self::$actions[$hook][] = $function;
            return TRUE;
        } 
 
        return FALSE ;
    }
 
	/**
     * executes the functions for the given hook
     * @param string $hook
     * @param array $params
     * @return boolean true if a hook was setted
     */
    public static function do_action($hook,$params=NULL)
    {
        $hook=mb_strtolower($hook,CHARSET);
        if(isset(self::$actions[$hook]))
        {
            // call each function handler associated with this hook
            foreach(self::$actions[$hook] as $function)
            {
                if (is_array($params))
                {
                    call_user_func_array($function,$params);
                }
                else 
                {
                    call_user_func($function);
                }
                //cant return anything since we are in a loop! dude!
            }
            return TRUE;
        }
        return FALSE;
    }
 
	/**
     * gets the functions for the given hook
     * @param string $hook
     * @return mixed 
     */
    public static function get_action($hook)
    {
        $hook=mb_strtolower($hook,CHARSET);
        return (isset(self::$actions[$hook]))? self::$actions[$hook]:FALSE;
    }
 
	/**
     * check exists the functions for the given hook
     * @param string $hook
     * @return boolean 
     */
    public static function exists_action($hook)
    {
        $hook=mb_strtolower($hook,CHARSET);
        return (isset(self::$actions[$hook]))? TRUE:FALSE;
    }
}
 
 
    /**
     * Hooks Shortcuts not in class
     */
    function add_action($hook,$function)
    {
        return Hook::add_action($hook,$function);
    }
 
    function do_action($hook)
    {
        return Hook::do_action($hook);
    }

gc_enable(); // Enable Garbage Collector
var_dump(gc_enabled()); // true
var_dump(gc_collect_cycles()); // # of elements cleaned up
gc_disable(); // Disable Garbage Collector

echo get_select_timezones('TIMEZONE',date_default_timezone_get());

///timezones functions
function get_timezones()
{
    if (method_exists('DateTimeZone','listIdentifiers'))
    {
        $timezones = array();
        $timezone_identifiers = DateTimeZone::listIdentifiers();
 
        foreach( $timezone_identifiers as $value )
        {
            if ( preg_match( '/^(America|Antartica|Arctic|Asia|Atlantic|Europe|Indian|Pacific)\//', $value ) )
            {
                $ex=explode('/',$value);//obtain continent,city
                $city = isset($ex[2])? $ex[1].' - '.$ex[2]:$ex[1];//in case a timezone has more than one
                $timezones[$ex[0]][$value] = $city;
            }
        }
        return $timezones;
    }
    else//old php version
    {
        return FALSE;
    }
}
 
 
 
function get_select_timezones($select_name='TIMEZONE',$selected=NULL)
{
    $timezones = get_timezones();
    $sel.='<select id="'.$select_name.'" name="'.$select_name.'">';
    foreach( $timezones as $continent=>$timezone )
    {
        $sel.= '<optgroup label="'.$continent.'">';
        foreach( $timezone as $city=>$cityname )
        {            
            if ($selected==$city)
            {
                $sel.= '<option selected=selected value="'.$city.'">'.$cityname.'</option>';
            }
            else $sel.= '<option value="'.$city.'">'.$cityname.'</option>';
        }
        $sel.= '</optgroup>';
    }
    $sel.='</select>';
 
    return $sel;
}

function curry($func, $arity) { 
    return create_function('', " 
        \$args = func_get_args(); 
        if(count(\$args) >= $arity) 
            return call_user_func_array('$func', \$args); 
        \$args = var_export(\$args, 1); 
        return create_function('',' 
            \$a = func_get_args(); 
            \$z = ' . \$args . '; 
            \$a = array_merge(\$z,\$a); 
            return call_user_func_array(\'$func\', \$a); 
        '); 
    "); 
} 
 
function sum($a, $b) { 
    return $a + $b; 
} 
 
$sum = curry('sum', 2); 
$plus5 = $sum(5); 
echo $plus5(10); // 15 
 
$map = curry('array_map', 2); 
$toupper = $map('strtoupper'); 
$ary = array('haskell', 'curry',); 
print_r($toupper($ary)); // HASKELL CURRY

function curry($func, $arity) {
    return create_function('', "
        \$args = func_get_args();
        if(count(\$args) >= $arity)
            return call_user_func_array('$func', \$args);
        \$args = var_export(\$args, 1);
        return create_function('','
            \$a = func_get_args();
            \$z = ' . \$args . ';
            \$a = array_merge(\$z,\$a);
            return call_user_func_array(\'$func\', \$a);
        ');
    ");
}
 
function on_match($transformation, $matches)
{
    return $transformation[strtolower($matches[1])];
}
 
$transform = array('a' => 'Well,', 'd'=>'whatever', 'b'=>' ');
 
$callback = curry(on_match, 2);
echo preg_replace_callback('/([a-z])/i', $callback($transform), 'Abcd');
 
echo "\n";