* @since 2.1
*/
public static ASTNode perform(ASTNode root, int start, int length) {
NodeFinder finder = new NodeFinder(start, length);
root.accept(finder);
ASTNode result = finder.getCoveredNode();
if (result == null || result.getStart() != start
|| result.getLength() != length) {
return finder.getCoveringNode();
}
return result;
}