Inject configuration settings into an input string
string $input Input to inject:
string
public function inject($input) {
  // Only perform the preg callback if needed
  return strpos($input, '{') === false ? $input : preg_replace_callback('/{\\s*([A-Za-z_\\-\\.0-9]+)\\s*}/', array(
    $this,
    'getPregMatchValue',
  ), $input);
}