Callback Extractor

This can be used to pass data from other php scripts.

By default Callback Extractor is disabled, as it need to have configured callback to do anything.

Example configuration with anonymous function:

$staple->preProcessors[] = [
            'class' => CallbackExtractor::class,
            'callback' => function($owner, $filename, $view){
                return ['message' => 'Hello World!']
            }
        ];

This will result in variable $data->message available in both view and template.

Multiple Callback Extractors can be used to call different callbacks.