Simple PHP block yielding system

blocks.php

<?php

function block($slug, $params = array()) {
  global $_SLUG_;
  global $_PARAMS_;

  $_SLUG_ = $slug;
  $_PARAMS_ = $params;
  
  ob_start();
}

function endblock() {
  global $_SLUG_;
  global $_PARAMS_;

  $yield = ob_get_clean();
  if(!isset($yield) || empty($yield)) $yield = '';
  
  foreach($_PARAMS_ as $key => $value) {
    $$key = $value;
  }

  $path = dirname(__FILE__) . '/' . $_SLUG_;
  require($path);
  
  unset($GLOBALS['_SLUG_']);
  unset($GLOBALS['_PARAMS_']);
}

?>

child.php

<div class="<?php echo $class ?>">
  <?php echo $yield; ?>
</div>

parent.php

<?php block('templates/child.php', array('class' => 'first')); ?>
  <p>Child 1</p>
<?php endblock(); ?>

<?php block('templates/child.php', array('class' => 'second')); ?>
  <p>Child 2</p>
<?php endblock(); ?>

result.html

<div class="first">
  <p>Child 1</p>
</div>

<div class="second">
  <p>Child 2</p>
</div>

Be sure your php.ini has output_buffering = On.