// lib/lib.php
<?php

class lib {

    protected function root() {
        return dirname(__FILE__);
    }


    protected function render($file_name, $variables_array = null) {

        if($variables_array)
            extract($variables_array);

        require($this->root() . '/../views/' . $file_name . '.php');
    }
}

// index.php
<?php

require('lib/lib.php');


class Application extends lib {

    public function run() {

        $var = '1st variable to use in a template';
        $var2 = '2nd variable to use in a template';

        $this->render('example', compact('var', 'var2'));
    }

}

$app = new Application();

$app->run();

// views/example.php
//some html here
<?php echo $var; echo $var2 ?>
//html...

// lib/lib.php
<?php

class lib {

    public $variables_array = array();

    protected function root() {
        return dirname(__FILE__);
    }

    protected function render($file_name) {
        if(isset($this->variables_array)) {
            extract($this->variables_array);                // Include external variables to use in a template
        }

        require_once($this->root() . "/../views/$file_name.php");
    }
}

?>

include('lib/lib.php');


class Application extends lib {

    public function run() {
        return $this->render('example');
    }

}

$app = new Application();
$app->variables_array=array('var'->'var text 1', 'var2'=>'var text 2');
$app->run();

?>

// views/example.php
//some html here
<?php echo $var; echo $var2 ?>
//html...