From eeecee4bdafff78abe9cf7da0f5900a7cfe211fa Mon Sep 17 00:00:00 2001
From: John Estabrook <jestabro@vyos.io>
Date: Tue, 25 Aug 2026 14:06:21 -0500
Subject: T9231: add util subtree_values_of_path

Get tag/leaf values of subtree defined by a partial path, for example, a
reference path.
---
 src/derived.ml  | 28 ++++++++++++++++++++++++++++
 src/derived.mli |  6 ++++++
 2 files changed, 34 insertions(+)

diff --git a/src/derived.ml b/src/derived.ml
index b980801..d1731f1 100644
--- a/src/derived.ml
+++ b/src/derived.ml
@@ -75,3 +75,31 @@ let subtree_from_partial ?(descent=true) reftree ctree result path =
             else
                 acc
     in aux result [] path
+
+
+let subtree_values_of_path rt ct path =
+    (* raises:
+        [Malformed_path] from subtree_from_partial
+     *)
+    let subtree = subtree_from_partial ~descent:false rt ct Config_tree.default path
+    in
+    if Util.is_empty path || subtree = Config_tree.default then
+        [([], [])]
+    else
+    let func (p, (acc, ct')) ft =
+        let path = List.rev p in
+        if Vytree.is_terminal_node ft then
+            let node = (Vytree.get[@alert "-exn"]) (ct': Config_tree.t) path in
+            let data = Vytree.data_of_node node in
+            let acc' =
+                if data.tag then ((Vytree.list_children node, path) :: acc)
+                else
+                if data.leaf then ((data.values, path) :: acc)
+                else acc
+            in (p, (acc', ct'))
+        else (p, (acc, ct'))
+    in fst (Vytree.fold_tree_with_path func ([], ([], ct)) subtree)
+
+let subtree_values_of_path_yojson rt ct path =
+    let ret = subtree_values_of_path rt ct path in
+    [%to_yojson: (string list * string list) list] ret |> Yojson.Safe.to_string
diff --git a/src/derived.mli b/src/derived.mli
index 61e4d8f..9ae2d26 100644
--- a/src/derived.mli
+++ b/src/derived.mli
@@ -2,3 +2,9 @@ exception Malformed_path of string
 
 val subtree_from_partial : ?descent:bool -> Reference_tree.t -> Config_tree.t -> Config_tree.t -> string list -> Config_tree.t
 [@@alert exn "Derived.Malformed_path"]
+
+val subtree_values_of_path : Reference_tree.t -> Config_tree.t -> string list -> (string list * string list) list
+[@@alert exn "Derived.Malformed_path"]
+
+val subtree_values_of_path_yojson : Reference_tree.t -> Config_tree.t -> string list -> string
+[@@alert exn "Derived.Malformed_path"]
-- 
cgit v1.2.3