3 files changed, 21 insertions, 7 deletions
diff --git a/parsing/extend.ml b/parsing/extend.ml
index 050ed49622..9b5537d7f6 100644
--- a/parsing/extend.ml
+++ b/parsing/extend.ml
@@ -106,11 +106,11 @@ type 'a production_rule =
 
 type 'a single_extend_statement =
   string option *
-  (** Level *)
+  (* Level *)
   Gramlib.Gramext.g_assoc option *
-  (** Associativity *)
+  (* Associativity *)
   'a production_rule list
-  (** Symbol list with the interpretation function *)
+  (* Symbol list with the interpretation function *)
 
 type 'a extend_statement =
   Gramlib.Gramext.position option *
diff --git a/parsing/tok.ml b/parsing/tok.ml
index 91b4f25ba3..c0d5b6742d 100644
--- a/parsing/tok.ml
+++ b/parsing/tok.ml
@@ -36,12 +36,24 @@ let equal t1 t2 = match t1, t2 with
 | EOI, EOI -> true
 | _ -> false
 
-let extract_string = function
+let extract_string diff_mode = function
   | KEYWORD s -> s
   | IDENT s -> s
-  | STRING s -> s
+  | STRING s ->
+   if diff_mode then
+    let escape_quotes s =
+      let len = String.length s in
+      let buf = Buffer.create len in
+      for i = 0 to len-1 do
+        let ch = String.get s i in
+        Buffer.add_char buf ch;
+        if ch = '"' then Buffer.add_char buf '"' else ()
+      done;
+      Buffer.contents buf
+    in
+    "\"" ^ (escape_quotes s) ^ "\"" else s
   | PATTERNIDENT s -> s
-  | FIELD s -> s
+  | FIELD s -> if diff_mode then "." ^ s else s
   | INT s -> s
   | LEFTQMARK -> "?"
   | BULLET s -> s
diff --git a/parsing/tok.mli b/parsing/tok.mli
index 9b8c008555..5750096a28 100644
--- a/parsing/tok.mli
+++ b/parsing/tok.mli
@@ -22,11 +22,13 @@ type t =
   | EOI
 
 val equal : t -> t -> bool
-val extract_string : t -> string
+(* pass true for diff_mode *)
+val extract_string : bool -> t -> string
 val to_string : t -> string
 (* Needed to fit Camlp5 signature *)
 val print : Format.formatter -> t -> unit
 val match_keyword : string -> t -> bool
+
 (** for camlp5 *)
 val of_pattern : string*string -> t
 val to_pattern : t -> string*string