another fix for PR#5090; this one seems to work correctly

git-svn-id: http://caml.inria.fr/svn/ocaml/version/3.12@10645 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02

6 files changed, 36 insertions, 28 deletions

diff --git a/VERSION b/VERSION
index d0c463f732..5ac4977b58 100644
--- a/VERSION
+++ b/VERSION
@@ -1,4 +1,4 @@
-3.12.1+dev1 (2010-08-13)
+3.12.1+dev2 (2010-08-13)
 
 # The version string is the first line of this file.
 # It must be in the format described in stdlib/sys.mli
diff --git a/camlp4/Camlp4/Struct/Grammar/Structure.ml b/camlp4/Camlp4/Struct/Grammar/Structure.ml
index c2afdd6395..67b99feb99 100644
--- a/camlp4/Camlp4/Struct/Grammar/Structure.ml
+++ b/camlp4/Camlp4/Struct/Grammar/Structure.ml
@@ -36,6 +36,7 @@ module type S = sig
 
   type token_info = { prev_loc : Loc.t
                     ; cur_loc : Loc.t
+                    ; prev_loc_only : bool
                     };
 
   type token_stream = Stream.t (Token.t * token_info);
@@ -126,6 +127,7 @@ module Make (Lexer  : Sig.Lexer) = struct
 
   type token_info = { prev_loc : Loc.t
                     ; cur_loc : Loc.t
+                    ; prev_loc_only : bool
                     };
 
   type token_stream = Stream.t (Token.t * token_info);
diff --git a/camlp4/Camlp4/Struct/Grammar/Tools.ml b/camlp4/Camlp4/Struct/Grammar/Tools.ml
index 26489d3744..31824eb285 100644
--- a/camlp4/Camlp4/Struct/Grammar/Tools.ml
+++ b/camlp4/Camlp4/Struct/Grammar/Tools.ml
@@ -16,6 +16,10 @@
  * - Daniel de Rauglaudre: initial version
  * - Nicolas Pouillard: refactoring
  *)
+
+(* PR#5090: don't do lookahead on get_prev_loc. *)
+value get_prev_loc_only = ref False;
+
 module Make (Structure : Structure.S) = struct
   open Structure;
 
@@ -29,10 +33,17 @@ module Make (Structure : Structure.S) = struct
   value keep_prev_loc strm =
     match Stream.peek strm with
     [ None -> [: :]
-    | Some (_,init_loc) ->
-      let rec go prev_loc = parser
-        [ [: `(tok,cur_loc); strm :] -> [: `(tok,{prev_loc;cur_loc}); go cur_loc strm :]
-        | [: :] -> [: :] ]
+    | Some (tok0,init_loc) ->
+      let rec go prev_loc strm1 =
+        if get_prev_loc_only.val then
+          [: `(tok0, {prev_loc; cur_loc = prev_loc; prev_loc_only = True});
+             go prev_loc strm1 :]
+        else
+          match strm1 with parser
+          [ [: `(tok,cur_loc); strm :] ->
+              [: `(tok, {prev_loc; cur_loc; prev_loc_only = False});
+                 go cur_loc strm :]
+          | [: :] -> [: :] ]
       in go init_loc strm ];
 
   value drop_prev_loc strm = stream_map (fun (tok,r) -> (tok,r.cur_loc)) strm;
@@ -43,9 +54,18 @@ module Make (Structure : Structure.S) = struct
     | None -> Loc.ghost ];
 
   value get_prev_loc strm =
-    match Stream.peek strm with
-    [ Some (_,r) -> r.prev_loc
-    | None -> Loc.ghost ];
+    do {
+      get_prev_loc_only.val := True;
+      let result = match Stream.peek strm with
+        [ Some (_, {prev_loc; prev_loc_only = True}) ->
+            do {Stream.junk strm; prev_loc}
+        | Some (_, {prev_loc; prev_loc_only = False}) -> prev_loc
+        | None -> Loc.ghost ]
+      in do {
+        get_prev_loc_only.val := False;
+        result
+      }
+    };
 
   value is_level_labelled n lev =
     match lev.lname with
diff --git a/camlp4/Camlp4Parsers/Camlp4OCamlParser.ml b/camlp4/Camlp4Parsers/Camlp4OCamlParser.ml
index 1bfdefc277..c7a510a52a 100644
--- a/camlp4/Camlp4Parsers/Camlp4OCamlParser.ml
+++ b/camlp4/Camlp4Parsers/Camlp4OCamlParser.ml
@@ -616,13 +616,11 @@ module Make (Syntax : Sig.Camlp4Syntax) = struct
         | `UIDENT s -> s
       ] ]
     ;
-    (* Fix for PR#5090: dummy tokens introduced by the toplevel's lexer
-       to compensate for the lookahead done by the location-handling code *)
     top_phrase:
-      [ [ OPT "%%dummy"; "#"; n = a_LIDENT; dp = opt_expr; ";;" ->
+      [ [ "#"; n = a_LIDENT; dp = opt_expr; ";;" ->
             Some <:str_item< # $n$ $dp$ >>
-        | OPT "%%dummy"; l = LIST1 str_item; ";;" -> Some (Ast.stSem_of_list l)
-        | OPT "%%dummy"; `EOI -> None
+        | l = LIST1 str_item; ";;" -> Some (Ast.stSem_of_list l)
+        | `EOI -> None
       ] ]
     ;
   END;
diff --git a/camlp4/Camlp4Parsers/Camlp4OCamlRevisedParser.ml b/camlp4/Camlp4Parsers/Camlp4OCamlRevisedParser.ml
index f91e6ab37b..11fd025041 100644
--- a/camlp4/Camlp4Parsers/Camlp4OCamlRevisedParser.ml
+++ b/camlp4/Camlp4Parsers/Camlp4OCamlRevisedParser.ml
@@ -1614,11 +1614,9 @@ Very old (no more supported) syntax:\n\
         | l = LIST0 [ st = str_item; semi -> st ] -> Ast.stSem_of_list l
       ] ]
     ;
-    (* Fix for PR#5090: dummy tokens introduced by the toplevel's lexer
-       to compensate for the lookahead done by the location-handling code *)
     top_phrase:
-      [ [ OPT "%% dummy %%"; ph = phrase -> Some ph
-        | OPT "%% dummy %%"; `EOI -> None
+      [ [ ph = phrase -> Some ph
+        | `EOI -> None
       ] ]
     ;
     use_file:
diff --git a/camlp4/Camlp4Top/Top.ml b/camlp4/Camlp4Top/Top.ml
index 66b3022aba..dcd3aa4607 100644
--- a/camlp4/Camlp4Top/Top.ml
+++ b/camlp4/Camlp4Top/Top.ml
@@ -62,15 +62,6 @@ end;
 
 value lookup x xs = try Some (List.assq x xs) with [ Not_found -> None ];
 
-(* Fix for PR#5090: dummy tokens introduced by the toplevel's lexer
-   to compensate for the lookahead done by the location-handling code *)
-value rec add_dummies x =
-  match x with parser
-  [ [: `(KEYWORD x, l); strm :] ->
-       [: `(KEYWORD x, l); `(KEYWORD "%% dummy %%", l); add_dummies strm :]
-  | [: `x; strm :] -> [: `x; add_dummies strm :] ]
-;
-
 value wrap parse_fun =
   let token_streams = ref [] in
   let cleanup lb =
@@ -110,8 +101,7 @@ value wrap parse_fun =
         } ];
 
 value toplevel_phrase token_stream =
-  match Gram.parse_tokens_after_filter Syntax.top_phrase
-                                       (add_dummies token_stream) with
+  match Gram.parse_tokens_after_filter Syntax.top_phrase token_stream with
     [ Some str_item ->
         let str_item =
           AstFilters.fold_topphrase_filters (fun t filter -> filter t) str_item