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Diffstat (limited to 'toplevel')
-rw-r--r--toplevel/coqloop.ml7
-rw-r--r--toplevel/g_toplevel.ml44
2 files changed, 11 insertions, 0 deletions
diff --git a/toplevel/coqloop.ml b/toplevel/coqloop.ml
index 64d839f18..371be20d2 100644
--- a/toplevel/coqloop.ml
+++ b/toplevel/coqloop.ml
@@ -338,6 +338,13 @@ let rec vernac_loop ~state =
try
let input = top_buffer.tokens in
match read_sentence ~state input with
+ | {v=VernacBacktrack(bid,_,_)} ->
+ let bid = Stateid.of_int bid in
+ let doc, res = Stm.edit_at ~doc:state.doc bid in
+ assert (res = `NewTip);
+ let state = { state with doc; sid = bid } in
+ vernac_loop ~state
+
| {v=VernacQuit} ->
exit 0
| {v=VernacDrop} ->
diff --git a/toplevel/g_toplevel.ml4 b/toplevel/g_toplevel.ml4
index 7526f3071..d5d558b9b 100644
--- a/toplevel/g_toplevel.ml4
+++ b/toplevel/g_toplevel.ml4
@@ -9,10 +9,12 @@
(************************************************************************)
open Pcoq
+open Pcoq.Prim
open Vernacexpr
(* Vernaculars specific to the toplevel *)
type vernac_toplevel =
+ | VernacBacktrack of int * int * int
| VernacDrop
| VernacQuit
| VernacControl of vernac_control
@@ -31,6 +33,8 @@ GEXTEND Gram
vernac_toplevel: FIRST
[ [ IDENT "Drop"; "." -> CAst.make VernacDrop
| IDENT "Quit"; "." -> CAst.make VernacQuit
+ | IDENT "Backtrack"; n = natural ; m = natural ; p = natural; "." ->
+ CAst.make (VernacBacktrack (n,m,p))
| cmd = main_entry ->
match cmd with
| None -> raise Stm.End_of_input