Refactoring: isolate two auxiliary functions out of [main_random].

src/Engine.ml

@@ -1389,6 +1389,36 @@ let main_afl source prologue fuel =
 
 (* -------------------------------------------------------------------------- *)
 
+(* [tick clock fuel] ticks the clock [clock] and, once in a while,
+   displays an information message. *)
+
+let[@inline] tick clock fuel =
+  Clock.tick clock @@ fun () ->
+    printf "%s tests run so far (%s/s overall, %s/s now) (fuel = %d).\n%!"
+      (summarize (Clock.ticks clock))
+      (summarize (Clock.overall_ticks_per_second clock))
+      (summarize (Clock.current_ticks_per_second clock))
+      fuel
+
+(* [log scenario fuel] logs the failure scenario [scenario] on
+   [stdout] and in a file in the directory ./output/crashes.*)
+
+let log scenario fuel =
+  (* Print the scenario to [stdout]. *)
+  output_string stdout scenario;
+  print_newline();
+  flush stdout;
+  (* Print the scenario into a file. *)
+  let temp_dir = "./output/crashes" in
+  mkdirp temp_dir;
+  let prefix = sprintf "scenario.%03d." fuel
+  and suffix = "" in
+  let _, oc = Filename.open_temp_file ~temp_dir prefix suffix in
+  output_string oc scenario;
+  close_out_noerr oc
+
+(* -------------------------------------------------------------------------- *)
+
 (* [main_random source prologue fuel] performs an unbounded number of test
    runs in random mode. *)
 
@@ -1417,32 +1447,12 @@ let rec main_random source prologue fuel =
       while true do
         (* Perform one run. *)
         run prologue fuel;
-        (* Roughly every second, display statistics. *)
-        Clock.tick clock begin fun () ->
-          printf "%s tests run so far (%s/s overall, %s/s now) (fuel = %d).\n%!"
-            (summarize (Clock.ticks clock))
-            (summarize (Clock.overall_ticks_per_second clock))
-            (summarize (Clock.current_ticks_per_second clock))
-            fuel
-        end
+        (* Tick the clock and, once in a while, display statistics. *)
+        tick clock fuel
       done
     end
   with Abort (scenario, fuel) ->
-    (* Print the scenario to [stdout]. This is necessary for the user
-       to be able to find out what happened. Also, log it to a file
-       in the directory ./output/crashes. *)
-    output_string stdout scenario;
-    print_newline();
-    flush stdout;
-
-    let temp_dir = "./output/crashes" in
-    mkdirp temp_dir;
-    let prefix = sprintf "scenario.%03d." fuel
-    and suffix = "" in
-    let _, oc = Filename.open_temp_file ~temp_dir prefix suffix in
-    output_string oc scenario;
-    close_out_noerr oc;
-
+    log scenario fuel;
     (* We have been able to find a problem with a certain amount of
        fuel. Try again, with this amount. This restricts our search
        space, and (with luck) we might now be able to find an even