final String greatest_common_prefix_up[] = analyzeSiblings( qnode_p, qnode_pp, separator );
res.setGreatestCommonPrefixUp( greatest_common_prefix_up[ 0 ] );
if ( greatest_common_prefix_up[ 1 ] != null ) {
final String greatest_common_prefix_up[] = analyzeSiblings( qnode_p, qnode_pp, separator );
res.setGreatestCommonPrefixUp( greatest_common_prefix_up[ 0 ] );
if ( greatest_common_prefix_up[ 1 ] != null ) {