2 files changed, 30 insertions, 0 deletions
diff --git a/lib/kernel/Path.ml b/lib/kernel/Path.ml
index 803d8cf..936704d 100644
--- a/lib/kernel/Path.ml
+++ b/lib/kernel/Path.ml
@@ -3,6 +3,23 @@ type t = string list
 let this = []
 let (@/) x y = x::y
 
+let to_string path =
+  path
+  |> List.map (fun x ->
+         let str = BatString.replace ~str:x ~sub:"^" ~by:"^^" |> snd in
+         BatString.replace ~str ~sub:"/" ~by:"^/" |> snd)
+  |> BatIO.to_string (BatList.print ~first:"/" ~last:"" ~sep:"/" BatString.print)
+
+module Error = struct
+  open Concepts.Condition
+
+  let path_not_found path = condition "path-not-found" "A given path was not found under the specified object"
+                              ("path" |=| Concepts.Value.String (to_string path))
+
+  let not_a_registry path = condition "not-a-registry" "The specified path did not point to a registry"
+                               ("path" |=| Concepts.Value.String (to_string path))
+end
+
 let rec lookup handle = function
   | [] -> Ok (Some handle)
   | x::xs ->
@@ -15,3 +32,13 @@ let rec lookup handle = function
         match elem with
         | None -> Ok None
         | Some elem -> lookup elem xs
+
+let lookup' handle path = lookup handle path
+                          |> Result.map (Option.to_result ~none:(Error.path_not_found path))
+                          |> Result.join
+
+let update handle path key reference value =
+  let open Utilities.Result in
+  let* handle = lookup' handle path in
+  let* registry = Protocols.Registry.from handle |> Option.to_result ~none:(Error.not_a_registry path) in
+  Protocols.Registry.update registry key reference value
diff --git a/lib/kernel/Path.mli b/lib/kernel/Path.mli
index 85d0ca9..e3eac9c 100644
--- a/lib/kernel/Path.mli
+++ b/lib/kernel/Path.mli
@@ -4,3 +4,6 @@ val this : t
 val (@/) : string -> t -> t
 
 val lookup : Protocols.Handle.t -> t -> (Protocols.Handle.t option, Concepts.Condition.condition) result
+val lookup' : Protocols.Handle.t -> t -> (Protocols.Handle.t, Concepts.Condition.condition) result
+
+val update : Protocols.Handle.t -> t -> string -> Protocols.Handle.t option -> Protocols.Handle.t option -> (bool, Concepts.Condition.condition) result