Add Config_tree.render_at_level function for correct rendering of configs for human consumption.

The idea of the correct (for subsequent parsing) and familiar for all other purposes rendering:
* When rendering the entire config, do not render the invisible "root" node, only render its children.
* When rendering config at specified path, do not include any nodes that are within the path
  (e.g. if path "system login" exists, "show system" request output should start with "login {",
   not "system { login { ...").

1 files changed, 18 insertions, 1 deletions

diff --git a/src/config_tree.ml b/src/config_tree.ml
index 9fed465..c816d65 100644
--- a/src/config_tree.ml
+++ b/src/config_tree.ml
@@ -156,7 +156,7 @@ struct
 
     let render
             ?(indent=4)
-            ?(reftree)
+            ?(reftree=None)
             ?(cmp=BatString.numeric_compare)
             ?(showephemeral=false)
             ?(showinactive=false)
@@ -249,3 +249,20 @@ struct
 end (* Renderer *)
 
 let render = Renderer.render
+
+let render_at_level
+  ?(indent=4)
+  ?(reftree=None)
+  ?(cmp=BatString.numeric_compare)
+  ?(showephemeral=false)
+  ?(showinactive=false)
+  node
+  path =
+    let node = 
+        match path with
+        | [] -> node
+        | _ -> Vytree.get node path
+    in
+    let children = Vytree.children_of_node node in
+    let child_configs = List.map (render ~indent:indent ~reftree:reftree  ~cmp:cmp ~showephemeral:showephemeral ~showinactive:showinactive) children in
+    List.fold_left (Printf.sprintf "%s\n%s") "" child_configs