Clock: internal change: replace [second] field with [last] field.

src/Clock.ml

@@ -22,8 +22,8 @@ type clock = {
   mutable now: float;
   (* The number of ticks that have taken place. *)
   mutable ticks: int;
-  (* The elapsed time, in integer seconds. *)
-  mutable second: int;
+  (* The last time [tick] was called for this clock. *)
+  mutable last: float;
   (* A circular array of the times at which the most recent round ticks
      took place. *)
   window: float array;
@@ -39,7 +39,7 @@ let make granularity =
     start;
     now = start;
     ticks = 0;
-    second = 0;
+    last = 0.;
     window = Array.make n start;
     next = 0;
   } in
@@ -55,11 +55,10 @@ let tick clock f =
     clock.window.(clock.next) <- clock.now;
     let n = Array.length clock.window in
     clock.next <- (clock.next + 1) mod n;
-    let second' = truncate (clock.now -. clock.start) in
     (* Check if roughly one new second has elapsed. If so, call the user
        function [f]. *)
-    if second' > clock.second then begin
-      clock.second <- second';
+    if clock.now > clock.last +. 1. then begin
+      clock.last <- clock.now;
       f()
     end
   end