| Preceding -> let ls2 = eval_axis tree ls (Ancestor true) in
let ls3 = eval_axis tree ls2 PrecedingSibling in
let lp = eval_axis tree ls3 (Descendant true) in
| Preceding -> let ls2 = eval_axis tree ls (Ancestor true) in
let ls3 = eval_axis tree ls2 PrecedingSibling in
let lp = eval_axis tree ls3 (Descendant true) in