diff --git a/src/froc/froc.ml b/src/froc/froc.ml
index 25644df..33afc8c 100644
--- a/src/froc/froc.ml
+++ b/src/froc/froc.ml
@@ -91,10 +91,10 @@ let make_event () = make_changeable ~eq:never_eq ()
 let never = make_constant (Fail Unset)
 let is_never = is_constant
 
-let notify_result_e_cancel t f = notify_result_cancel ~current:false t f
-let notify_result_e t f = notify_result ~current:false t f
-let notify_e_cancel t f = notify_cancel ~current:false t f
-let notify_e t f = notify ~current:false t f
+let notify_result_e_cancel t f = notify_result_cancel ~now:false t f
+let notify_result_e t f = notify_result ~now:false t f
+let notify_e_cancel t f = notify_cancel ~now:false t f
+let notify_e t f = notify ~now:false t f
 
 let hash_event = hash
 
@@ -116,16 +116,13 @@ let merge ts =
   if List.for_all is_never ts then never
   else
     let rt, ru = make_event () in
-    let notify = ref false in
-    add_readerN ts begin fun () ->
-      if not !notify then notify := true
-      else
-        let rec loop = function
-          | [] -> assert false
-          | h :: t ->
-              match read_result h with
-                | Fail Unset -> loop t
-                | r -> r in
+    add_readerN ~now:false ts begin fun () ->
+      let rec loop = function
+        | [] -> assert false
+        | h :: t ->
+            match read_result h with
+              | Fail Unset -> loop t
+              | r -> r in
         write_temp_result ru (loop ts)
     end;
     rt
@@ -147,21 +144,18 @@ let map2 f t1 t2 =
   if is_never t1 && is_never t2 then never
   else
     let rt, ru = make_event () in
-    let notify = ref false in
-    add_reader2 t1 t2 begin fun () ->
-      if not !notify then notify := true
-      else
-        let r =
-          match read_result t1, read_result t2 with
-            | Fail Unset, _
-            | _, Fail Unset -> None
-            | Fail e, _
-            | _, Fail e -> Some (Fail e)
-            | Value v1, Value v2 ->
-                try Some (Value (f v1 v2)) with e -> Some (Fail e) in
-        match r with
-          | None -> ()
-          | Some r -> write_temp_result ru r
+    add_reader2 ~now:false t1 t2 begin fun () ->
+      let r =
+        match read_result t1, read_result t2 with
+          | Fail Unset, _
+          | _, Fail Unset -> None
+          | Fail e, _
+          | _, Fail e -> Some (Fail e)
+          | Value v1, Value v2 ->
+              try Some (Value (f v1 v2)) with e -> Some (Fail e) in
+      match r with
+        | None -> ()
+        | Some r -> write_temp_result ru r
     end;
     rt
 
@@ -259,7 +253,7 @@ let hold ?eq init e = hold_result ?eq (Value init) e
 let changes b =
   if is_constant b then never else
     let t, u = make_event () in
-    notify_result_b ~current:false b (write_temp_result u);
+    notify_result_b ~now:false b (write_temp_result u);
     t
 
 let when_true b =
diff --git a/src/froc/froc.mli b/src/froc/froc.mli
index 2ace889..0abb903 100644
--- a/src/froc/froc.mli
+++ b/src/froc/froc.mli
@@ -183,7 +183,7 @@ val fix_b : ?eq:('a -> 'a -> bool) -> ('a behavior -> 'a behavior) -> 'a behavio
      delayed one update cycle.
   *)
 
-val notify_b : ?current:bool -> 'a behavior -> ('a -> unit) -> unit
+val notify_b : ?now:bool -> 'a behavior -> ('a -> unit) -> unit
   (**
      [notify_b b f] adds [f] as a listener for [b], which is called
      whenever [b] changes. When [b] fails the listener is not
@@ -191,24 +191,24 @@ val notify_b : ?current:bool -> 'a behavior -> ('a -> unit) -> unit
      scope is cleaned up.
      
      The listener is called immediately with the current value of the
-     behavior, unless [current] is false. The function [f] delimits a
+     behavior, unless [now] is false. The function [f] delimits a
      dynamic scope governed by [b].
   *)
 
-val notify_b_cancel : ?current:bool -> 'a behavior -> ('a -> unit) -> cancel
+val notify_b_cancel : ?now:bool -> 'a behavior -> ('a -> unit) -> cancel
   (**
 
      Same as [notify_b], and returns a cancel handle (the notification
      is still cancelled when the enclosing dynamic scope is cleaned up).
   *)
 
-val notify_result_b : ?current:bool -> 'a behavior -> ('a result -> unit) -> unit
+val notify_result_b : ?now:bool -> 'a behavior -> ('a result -> unit) -> unit
   (**
      Same as [notify_b] but the listener is called with a result when
      the value changes or when the behavior fails.
   *)
 
-val notify_result_b_cancel : ?current:bool -> 'a behavior -> ('a result -> unit) -> cancel
+val notify_result_b_cancel : ?now:bool -> 'a behavior -> ('a result -> unit) -> cancel
   (**
      Same as [notify_result_b], and returns a cancel handle (the
      notification is still cancelled when the enclosing dynamic scope
diff --git a/src/froc/froc_ddg.ml b/src/froc/froc_ddg.ml
index 0689373..8046d94 100644
--- a/src/froc/froc_ddg.ml
+++ b/src/froc/froc_ddg.ml
@@ -249,14 +249,21 @@ let init () =
 
 let enqueue e = PQ.add !pq e
 
-let add_reader_cancel t read =
+let read_now ?(now=true) read =
+  if now then read
+  else
+    let notify = ref false in
+    fun () -> if not !notify then notify := true else read ()
+
+let add_reader_cancel ?now t read =
+  let read = read_now ?now read in
   let start = TS.tick () in
   read ();
   let r = { read = read; start = start; finish = TS.tick () } in
   let dep _ = enqueue r in
   add_dep_cancel start t dep
 
-let add_reader t read = let _ = add_reader_cancel t read in ()
+let add_reader ?now t read = let _ = add_reader_cancel ?now t read in ()
 
 let connect_cancel u t' =
   write_result u (read_result t');
@@ -266,27 +273,18 @@ let connect u t' =
   write_result u (read_result t');
   add_dep (TS.tick ()) t' (write_result_no_eq u)
 
-let notify_result_cancel ?(current=true) t f =
-  if current
-  then
-    add_reader_cancel t begin fun () ->
-      try f (read_result t) with e -> !handle_exn e
-    end
-  else
-    let notify = ref false in
-    add_reader_cancel t begin fun () ->
-      if not !notify then notify := true
-      else
-        try f (read_result t) with e -> !handle_exn e
-    end
+let notify_result_cancel ?now t f =
+  add_reader_cancel ?now t begin fun () ->
+    try f (read_result t) with e -> !handle_exn e
+  end
 
-let notify_result ?current t f = let _ = notify_result_cancel ?current t f in ()
+let notify_result ?now t f = let _ = notify_result_cancel ?now t f in ()
 
-let notify_cancel ?current t f =
-  notify_result_cancel ?current t (function Fail _ -> () | Value v -> f v)
+let notify_cancel ?now t f =
+  notify_result_cancel ?now t (function Fail _ -> () | Value v -> f v)
 
-let notify ?current t f =
-  notify_result ?current t (function Fail _ -> () | Value v -> f v)
+let notify ?now t f =
+  notify_result ?now t (function Fail _ -> () | Value v -> f v)
 
 let cleanup f =
   TS.add_cleanup (TS.tick ()) f
@@ -400,7 +398,8 @@ let memo ?size ?hash ?eq () =
         result in
     match result with Value v -> v | Fail e -> raise e
 
-let add_reader2 t1 t2 read =
+let add_reader2 ?now t1 t2 read =
+  let read = read_now ?now read in
   let start = TS.tick () in
   read ();
   let r = { read = read; start = start; finish = TS.tick () } in
@@ -427,7 +426,8 @@ let bind2 ?eq t1 t2 f = bind2_gen ?eq identity connect f t1 t2
 let lift2 ?eq f = bind2_gen ?eq return write f
 let blift2 ?eq t1 t2 f = lift2 ?eq f t1 t2
 
-let add_reader3 t1 t2 t3 read =
+let add_reader3 ?now t1 t2 t3 read =
+  let read = read_now ?now read in
   let start = TS.tick () in
   read ();
   let r = { read = read; start = start; finish = TS.tick () } in
@@ -457,7 +457,8 @@ let bind3 ?eq t1 t2 t3 f = bind3_gen ?eq identity connect f t1 t2 t3
 let lift3 ?eq f = bind3_gen ?eq return write f
 let blift3 ?eq t1 t2 t3 f = lift3 ?eq f t1 t2 t3
 
-let add_reader4 t1 t2 t3 t4 read =
+let add_reader4 ?now t1 t2 t3 t4 read =
+  let read = read_now ?now read in
   let start = TS.tick () in
   read ();
   let r = { read = read; start = start; finish = TS.tick () } in
@@ -493,7 +494,8 @@ let bind4 ?eq t1 t2 t3 t4 f = bind4_gen ?eq identity connect f t1 t2 t3 t4
 let lift4 ?eq f = bind4_gen ?eq return write f
 let blift4 ?eq t1 t2 t3 t4 f = lift4 ?eq f t1 t2 t3 t4
 
-let add_reader5 t1 t2 t3 t4 t5 read =
+let add_reader5 ?now t1 t2 t3 t4 t5 read =
+  let read = read_now ?now read in
   let start = TS.tick () in
   read ();
   let r = { read = read; start = start; finish = TS.tick () } in
@@ -532,7 +534,8 @@ let bind5 ?eq t1 t2 t3 t4 t5 f = bind5_gen ?eq identity connect f t1 t2 t3 t4 t5
 let lift5 ?eq f = bind5_gen ?eq return write f
 let blift5 ?eq t1 t2 t3 t4 t5 f = lift5 ?eq f t1 t2 t3 t4 t5
 
-let add_reader6 t1 t2 t3 t4 t5 t6 read =
+let add_reader6 ?now t1 t2 t3 t4 t5 t6 read =
+  let read = read_now ?now read in
   let start = TS.tick () in
   read ();
   let r = { read = read; start = start; finish = TS.tick () } in
@@ -575,7 +578,8 @@ let bind6 ?eq t1 t2 t3 t4 t5 t6 f = bind6_gen ?eq identity connect f t1 t2 t3 t4
 let lift6 ?eq f = bind6_gen ?eq return write f
 let blift6 ?eq t1 t2 t3 t4 t5 t6 f = lift6 ?eq f t1 t2 t3 t4 t5 t6
 
-let add_reader7 t1 t2 t3 t4 t5 t6 t7 read =
+let add_reader7 ?now t1 t2 t3 t4 t5 t6 t7 read =
+  let read = read_now ?now read in
   let start = TS.tick () in
   read ();
   let r = { read = read; start = start; finish = TS.tick () } in
@@ -621,7 +625,8 @@ let bind7 ?eq t1 t2 t3 t4 t5 t6 t7 f = bind7_gen ?eq identity connect f t1 t2 t3
 let lift7 ?eq f = bind7_gen ?eq return write f
 let blift7 ?eq t1 t2 t3 t4 t5 t6 t7 f = lift7 ?eq f t1 t2 t3 t4 t5 t6 t7
 
-let add_readerN ts read =
+let add_readerN ?now ts read =
+  let read = read_now ?now read in
   let start = TS.tick () in
   read ();
   let r = { read = read; start = start; finish = TS.tick () } in
diff --git a/src/froc/froc_ddg.mli b/src/froc/froc_ddg.mli
index 6bba94e..662df68 100644
--- a/src/froc/froc_ddg.mli
+++ b/src/froc/froc_ddg.mli
@@ -42,8 +42,8 @@ val bind : ?eq:('b -> 'b -> bool) -> 'a t -> ('a -> 'b t) -> 'b t
 val (>>=) : 'a t -> ('a -> 'b t) -> 'b t
 val lift : ?eq:('b -> 'b -> bool) -> ('a -> 'b) -> 'a t -> 'b t 
 val blift : ?eq:('b -> 'b -> bool) -> 'a t -> ('a -> 'b) -> 'b t
-val add_reader : 'a t -> (unit -> unit) -> unit
-val add_reader_cancel : 'a t -> (unit -> unit) -> cancel
+val add_reader : ?now:bool -> 'a t -> (unit -> unit) -> unit
+val add_reader_cancel : ?now:bool -> 'a t -> (unit -> unit) -> cancel
 
 val catch : ?eq:('a -> 'a -> bool) -> (unit -> 'a t) -> (exn -> 'a t) -> 'a t
 val try_bind : ?eq:('b -> 'b -> bool) -> (unit -> 'a t) -> ('a -> 'b t) -> (exn -> 'b t) -> 'b t
@@ -57,10 +57,10 @@ val write_exn : 'a u -> exn -> unit
 val write_result : 'a u -> 'a result -> unit
 val clear : 'a u -> unit
 
-val notify : ?current:bool -> 'a t -> ('a -> unit) -> unit
-val notify_cancel : ?current:bool -> 'a t -> ('a -> unit) -> cancel
-val notify_result : ?current:bool -> 'a t -> ('a result -> unit) -> unit
-val notify_result_cancel : ?current:bool -> 'a t -> ('a result -> unit) -> cancel
+val notify : ?now:bool -> 'a t -> ('a -> unit) -> unit
+val notify_cancel : ?now:bool -> 'a t -> ('a -> unit) -> cancel
+val notify_result : ?now:bool -> 'a t -> ('a result -> unit) -> unit
+val notify_result_cancel : ?now:bool -> 'a t -> ('a result -> unit) -> cancel
 val connect : 'a u -> 'a t -> unit
 val connect_cancel : 'a u -> 'a t -> cancel
 val cleanup : (unit -> unit) -> unit
@@ -96,6 +96,7 @@ val blift2 :
   ('a1 -> 'a2 -> 'b) ->
   'b t
 val add_reader2 :
+  ?now:bool ->
   'a1 t -> 'a2 t ->
   (unit -> unit) -> unit
 
@@ -115,6 +116,7 @@ val blift3 :
   ('a1 -> 'a2 -> 'a3 -> 'b) ->
   'b t
 val add_reader3 :
+  ?now:bool ->
   'a1 t -> 'a2 t -> 'a3 t ->
   (unit -> unit) -> unit
 
@@ -134,6 +136,7 @@ val blift4 :
   ('a1 -> 'a2 -> 'a3 -> 'a4 -> 'b) ->
   'b t
 val add_reader4 :
+  ?now:bool ->
   'a1 t -> 'a2 t -> 'a3 t -> 'a4 t ->
   (unit -> unit) -> unit
 
@@ -153,6 +156,7 @@ val blift5 :
   ('a1 -> 'a2 -> 'a3 -> 'a4 -> 'a5 -> 'b) ->
   'b t
 val add_reader5 :
+  ?now:bool ->
   'a1 t -> 'a2 t -> 'a3 t -> 'a4 t -> 'a5 t ->
   (unit -> unit) -> unit
 
@@ -172,6 +176,7 @@ val blift6 :
   ('a1 -> 'a2 -> 'a3 -> 'a4 -> 'a5 -> 'a6 -> 'b) ->
   'b t
 val add_reader6 :
+  ?now:bool ->
   'a1 t -> 'a2 t -> 'a3 t -> 'a4 t -> 'a5 t -> 'a6 t ->
   (unit -> unit) -> unit
 
@@ -191,10 +196,11 @@ val blift7 :
   ('a1 -> 'a2 -> 'a3 -> 'a4 -> 'a5 -> 'a6 -> 'a7 -> 'b) ->
   'b t
 val add_reader7 :
+  ?now:bool ->
   'a1 t -> 'a2 t -> 'a3 t -> 'a4 t -> 'a5 t -> 'a6 t -> 'a7 t ->
   (unit -> unit) -> unit
 
 val bindN : ?eq:('b -> 'b -> bool) -> 'a t list -> ('a list -> 'b t) -> 'b t
 val liftN : ?eq:('b -> 'b -> bool) -> ('a list -> 'b) -> 'a t list -> 'b t
 val bliftN : ?eq:('b -> 'b -> bool) -> 'a t list -> ('a list -> 'b) -> 'b t
-val add_readerN : 'a t list -> (unit -> unit) -> unit
+val add_readerN : ?now:bool -> 'a t list -> (unit -> unit) -> unit