X-Git-Url: http://git.nguyen.vg/gitweb/?p=tatoo.git;a=blobdiff_plain;f=src%2Fnaive_tree.ml;h=a13a56dd21b1616283df446ad9fe383c39ba2728;hp=38421e0ad766ec72799de4f75bc9872fffa84ab8;hb=1947a98f419c2bf50378fed783406818b010c60e;hpb=57fd66649f11c7f513d389d3ee5c02cc24bc51c7

diff --git a/src/naive_tree.ml b/src/naive_tree.ml
index 38421e0..a13a56d 100644
--- a/src/naive_tree.ml
+++ b/src/naive_tree.ml
@@ -327,6 +327,13 @@ let root t = t.root
 let size t = t.size
 let first_child _ n = n.first_child
 let next_sibling _ n = n.next_sibling
+
+let is_first_child _ n = n.parent.first_child == n
+let is_next_sibling _ n = n.parent.next_sibling == n
+
+let prev_sibling t n = if is_next_sibling t n then n.parent else nil
+let parent_of_first t n = if is_first_child t n then n.parent else nil
+
 let parent _ n = n.parent
 let tag _ n = n.tag
 let data _ n = n.data