Introduce constants for StatementGrouper names

thiemowmde · thiemowmde · commit e52b15373118 · 2015-12-14T11:21:09.000+01:00
diff --git a/src/Statement/ReferencedStatementFilter.php b/src/Statement/ReferencedStatementFilter.php
@@ -10,6 +10,11 @@
  */
 class ReferencedStatementFilter implements StatementFilter {
 
+	/**
+	 * @since 4.4
+	 */
+	const FILTER_TYPE = 'referenced';
+
 	/**
 	 * @param Statement $statement
 	 *
