Get variables from included file

How do I use variables from an included file, and use it for other included files as well?

index

<?php
$tmp = new template($connect);
$tmp->globals('index');
$logged_in = false; //works in all included files
?>
<html>
  <head>
    <?php $tmp->template('head'); ?> //class method to include file
  </head>
  <body>
    <?php echo $description; ?> //does not work either

include_head.php

 <title><?php echo $title; ?></title>//does not echo anything

index_globals.php

<?php
    $title="title";
    $description="description";   
 ?>

How I am including

public function template($file){
    if(isset($file) && file_exists($this->dir.$file.".php")){
        ob_start();
        include($this->dir.$file.".php");
        $template = ob_get_contents();
        return $template;
     }
}

Globals Function

public function globals($name){
  if(isset($name) && file_exists($this->dir.$name."_globals.php")){
      include($this->dir.$name."_globals.php");
  }
}

Solution

You can "import" the globals by returning an array instead of declaring the variables:

<?php
// index_globals.php

return [
    'title' => 'title',
    'description' => 'description',
];

Then, from the globals() function you import it into a local property:

private $context = [];

public function globals($name)
{
    if (isset($name) && file_exists($this->dir.$name."_globals.php")) {
        $this->context = include($this->dir.$name."_globals.php");
    }
}

Finally, update the template() method:

public function template($file)
{
    if (isset($file) && file_exists($this->dir.$file.".php")) {
        extract($this->context);
        ob_start();
        include($this->dir.$file.".php");
        $template = ob_get_contents();
        return $template;
     }
}

Note that your index will not have access to $description in this case either, but it shouldn't be hard to gain access via the template instance.