From 677d5deb72734a0e5502bcf47a905fcdf9374e51 Mon Sep 17 00:00:00 2001
From: Matthieu Sozeau
Date: Fri, 20 May 2016 03:18:41 +0200
Subject: Proofview: extensions for backtracking eauto

unshelve_goals is used to correctly register dependent
subgoals that have to be solved. Resolution may fail to
do so using hints, so we have to put them back as goals
in that case. The shelf is a good interface for doing that.

unifiable can be used outside proofview to detect dependencies
between goals. This might be better in another module.
---
 engine/proofview.ml  |  7 +++++++
 engine/proofview.mli | 10 ++++++++++
 2 files changed, 17 insertions(+)

(limited to 'engine')

diff --git a/engine/proofview.ml b/engine/proofview.ml
index b8f49a9c84..d876860652 100644
--- a/engine/proofview.ml
+++ b/engine/proofview.ml
@@ -618,6 +618,13 @@ let shelve =
   InfoL.leaf (Info.Tactic (fun () -> Pp.str"shelve")) >>
   Shelf.modify (fun gls -> gls @ initial)
 
+let shelve_goals l =
+  let open Proof in
+  Comb.get >>= fun initial ->
+  let comb = CList.filter (fun g -> not (CList.mem g l)) initial in
+  Comb.set comb >>
+  InfoL.leaf (Info.Tactic (fun () -> Pp.str"shelve_goals")) >>
+  Shelf.modify (fun gls -> gls @ l)
 
 (** [contained_in_info e evi] checks whether the evar [e] appears in
     the hypotheses, the conclusion or the body of the evar_info
diff --git a/engine/proofview.mli b/engine/proofview.mli
index 0b63164b09..901cf26e0e 100644
--- a/engine/proofview.mli
+++ b/engine/proofview.mli
@@ -300,6 +300,16 @@ val tclINDEPENDENT : unit tactic -> unit tactic
     shelf for later use (or being solved by side-effects). *)
 val shelve : unit tactic
 
+(** Shelves the given list of goals, which might include some that are
+    under focus and some that aren't. All the goals are placed on the
+    shelf for later use (or being solved by side-effects). *)
+val shelve_goals : Goal.goal list -> unit tactic
+
+(** [unifiable sigma g l] checks whether [g] appears in another
+    subgoal of [l]. The list [l] may contain [g], but it does not
+    affect the result. Used by [shelve_unifiable]. *)
+val unifiable : Evd.evar_map -> Goal.goal -> Goal.goal list -> bool
+
 (** Shelves the unifiable goals under focus, i.e. the goals which
     appear in other goals under focus (the unfocused goals are not
     considered). *)
-- 
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