'< \[\[ ([^]]*) \]\] >x',
function ($sub) use ($blocks) {
list ($placeholder, $name) = $sub;
- $html = $blocks[$name];
+ if (isset($blocks[$name])) {
+ $html = $blocks[$name];
+ }
+ else {
+ $html = '<strong class="warn"><em>'.$name.'</em> ontbreekt</strong>';
+ }
return sprintf('<!--BLOCK:%s-->%s<!--/-->',
is_numeric($name) ? '' : $placeholder, # edit replacement
preg_replace('{<!--[^-]*-->}', '', $html) # contents