Correctly flush the toplevel output in case the lexer consumes the

"\n" after the ;; token.

driver/run.ml

@@ -103,6 +103,18 @@ let outflush s =
   output_string stdout s;
   flush stdout
 
+let has_newline b =
+  let rec loop i found =
+    if i >= 1 then
+      let c = Buffer.nth b i in
+      if c == ';' && Buffer.nth b (i-1) == ';'
+      then found
+      else loop (i - 1) (c == '\n')
+    else false
+  in
+  loop (Buffer.length b - 1) false
+
+
 let toploop () =
   let restore = 
     try 
@@ -141,6 +153,8 @@ let toploop () =
     bol := false;
     Buffer.clear buf_in;
     ignore (Cduce.topinput ppf ppf_err input);
+    if not (has_newline buf_in) then
+      (* ";;\n" was eaten by a regular expression in the lexer *)
     while (input_char stdin != '\n') do () done;
     loop () in
   (try loop () with End_of_file -> ());