4 files changed, 17 insertions, 5 deletions
diff --git a/_oasis b/_oasis
index 34701d0..6075221 100644
--- a/_oasis
+++ b/_oasis
@@ -13,7 +13,7 @@ Plugins: META (0.4), DevFiles (0.4)
 
 Library "vyconf"
   Path: src
-  Modules: Vytree, Vylist, Value_checker, Vyconf_config
+  Modules: Vytree, Vylist, Value_checker, Vyconf_config, Util
   Install: false
 
 Library "vytree"
diff --git a/setup.ml b/setup.ml
index 849789c..c343339 100644
--- a/setup.ml
+++ b/setup.ml
@@ -1,7 +1,7 @@
 (* setup.ml generated for the first time by OASIS v0.4.8 *)
 
 (* OASIS_START *)
-(* DO NOT EDIT (digest: 602702c2b3e29065636a02e0e82ba6a6) *)
+(* DO NOT EDIT (digest: d662f8d4da0a60b09228a8655e62c2a8) *)
 (*
    Regenerated by OASIS v0.4.8
    Visit http://oasis.forge.ocamlcore.org for more information and
@@ -7380,7 +7380,12 @@ let setup_t =
                    },
                    {
                       lib_modules =
-                        ["Vytree"; "Vylist"; "Value_checker"; "Vyconf_config"
+                        [
+                           "Vytree";
+                           "Vylist";
+                           "Value_checker";
+                           "Vyconf_config";
+                           "Util"
                         ];
                       lib_pack = false;
                       lib_internal_modules = [];
@@ -11336,7 +11341,7 @@ let setup_t =
        };
      oasis_fn = Some "_oasis";
      oasis_version = "0.4.8";
-     oasis_digest = Some "\164\128uZ\195\226\174r\220\161\232Msu\141\165";
+     oasis_digest = Some "#Iza,I\028\140\r \250\017\0166\000C";
      oasis_exec = None;
      oasis_setup_args = [];
      setup_update = false
@@ -11344,7 +11349,7 @@ let setup_t =
 
 let setup () = BaseSetup.setup setup_t;;
 
-# 11348 "setup.ml"
+# 11353 "setup.ml"
 let setup_t = BaseCompat.Compat_0_4.adapt_setup_t setup_t
 open BaseCompat.Compat_0_4
 (* OASIS_STOP *)
diff --git a/src/util.ml b/src/util.ml
index b45f011..2bac3d6 100644
--- a/src/util.ml
+++ b/src/util.ml
@@ -20,3 +20,8 @@ let string_of_path path =
     match path with
     | [] -> ""
     | x :: xs -> Printf.sprintf "%s%s" x (aux xs "")
+
+let substitute_default o d =
+    match o with
+    | None -> d
+    | Some v -> v
diff --git a/src/util.mli b/src/util.mli
index ec0bb73..7d78a15 100644
--- a/src/util.mli
+++ b/src/util.mli
@@ -1,3 +1,5 @@
 val find_xml_child : string -> Xml.xml -> Xml.xml option
 
 val string_of_path : string list -> string
+
+val substitute_default : 'a option -> 'a -> 'a