+external tree_first_element : tree -> [`Tree] node -> [`Tree] node = "caml_xml_tree_first_element" "noalloc"
+external tree_last_child : tree -> [`Tree] node -> [`Tree] node = "caml_xml_tree_last_child" "noalloc"
+external tree_next_sibling : tree -> [`Tree] node -> [`Tree] node = "caml_xml_tree_next_sibling" "noalloc"
+external tree_next_element : tree -> [`Tree] node -> [`Tree] node = "caml_xml_tree_next_element" "noalloc"
+external tree_prev_sibling : tree -> [`Tree] node -> [`Tree] node = "caml_xml_tree_prev_sibling" "noalloc"
+external tree_tagged_child : tree -> [`Tree] node -> Tag.t -> [`Tree] node = "caml_xml_tree_tagged_child" "noalloc"
+
+type unordered_set
+external unordered_set_alloc : int -> unordered_set = "caml_unordered_set_alloc"
+external unordered_set_length : unordered_set -> int = "caml_unordered_set_length"
+external unordered_set_insert : unordered_set -> int -> unit = "caml_unordered_set_set" "noalloc"
+
+external tree_select_child : tree -> [`Tree ] node -> unordered_set -> [`Tree] node = "caml_xml_tree_select_child" "noalloc"
+external tree_tagged_following_sibling : tree -> [`Tree] node -> Tag.t -> [`Tree] node = "caml_xml_tree_tagged_following_sibling" "noalloc"
+external tree_select_following_sibling : tree -> [`Tree ] node -> unordered_set -> [`Tree] node = "caml_xml_tree_select_following_sibling" "noalloc"
+external tree_tagged_descendant : tree -> [`Tree ] node -> Tag.t -> [`Tree ] node = "caml_xml_tree_tagged_descendant" "noalloc"
+external tree_select_descendant : tree -> [`Tree ] node -> unordered_set -> [`Tree] node = "caml_xml_tree_select_descendant" "noalloc"
+external tree_tagged_following : tree -> [`Tree ] node -> Tag.t -> [`Tree ] node = "caml_xml_tree_tagged_following" "noalloc"
+external tree_tagged_following_below : tree -> [`Tree ] node -> Tag.t -> [`Tree ] node -> [`Tree ] node = "caml_xml_tree_tagged_following_below" "noalloc"
+external tree_select_following_below : tree -> [`Tree ] node -> unordered_set -> [`Tree] node -> [`Tree] node = "caml_xml_tree_select_following_below" "noalloc"
+
+
+external tree_tagged_following_before : tree -> [`Tree ] node -> Tag.t -> [`Tree ] node -> [`Tree ] node = "caml_xml_tree_tagged_following_before" "noalloc"
+external tree_select_following_below : tree -> [`Tree ] node -> unordered_set -> [`Tree] node -> [`Tree] node = "caml_xml_tree_select_following_before" "noalloc"
+
+external tree_my_text : tree -> [`Tree ] node -> [`Text] node = "caml_xml_tree_my_text" "noalloc"
+external tree_my_text_unsafe : tree -> [`Tree ] node -> [`Text] node = "caml_xml_tree_my_text_unsafe" "noalloc"
+external tree_text_xml_id : tree -> [`Text ] node -> int = "caml_xml_tree_text_xml_id" "noalloc"
+external tree_node_xml_id : tree -> [`Tree ] node -> int = "caml_xml_tree_node_xml_id" "noalloc"
+
+external tree_parent_node : tree -> [`Text ] node -> [`Tree ] node = "caml_xml_tree_parent_node" "noalloc"
+
+(*external tree_prev_doc : tree -> [`Text ] node -> [`Tree ] node = "caml_xml_tree_prev_doc" "noalloc" *)
+