Remove the Sigma (monotonous state) API.

Reminder of (some of) the reasons for removal:

- Despite the claim in sigma.mli, it does *not* prevent evar
  leaks, something like:

  fun env evd ->
  let (evd',ev) = new_evar env evd in
  (evd,ev)

  will typecheck even with Sigma-like type annotations (with a proof of
  reflexivity)

- The API stayed embryonic. Even typing functions were not ported to
  Sigma.

- Some unsafe combinators (Unsafe.tclEVARS) were replaced with slightly
  less unsafe ones (e.g. s_enter), but those ones were not marked unsafe
  at all (despite still being so).

- There was no good story for higher order functions manipulating evar
  maps. Without higher order, one can most of the time get away with
  reusing the same name for the updated evar map.

- Most of the code doing complex things with evar maps was using unsafe
  casts to sigma. This code should be fixed, but this is an orthogonal
  issue.

Of course, this was showing a nice and elegant use of GADTs, but the
cost/benefit ratio in practice did not seem good.

1 files changed, 16 insertions, 16 deletions

diff --git a/plugins/firstorder/rules.ml b/plugins/firstorder/rules.ml
index f745dbeb4..b7fe25a32 100644
--- a/plugins/firstorder/rules.ml
+++ b/plugins/firstorder/rules.ml
@@ -32,7 +32,7 @@ type lseqtac= global_reference -> seqtac
 type 'a with_backtracking = tactic -> 'a
 
 let wrap n b continue seq =
-  Proofview.Goal.nf_enter { enter = begin fun gls ->
+  Proofview.Goal.nf_enter begin fun gls ->
   Control.check_for_interrupt ();
   let nc = Proofview.Goal.hyps gls in
   let env=pf_env gls in
@@ -52,7 +52,7 @@ let wrap n b continue seq =
   let seq2=if b then
     add_formula env sigma Concl dummy_id (pf_concl gls) seq1 else seq1 in
     continue seq2
-  end }
+  end
 
 let basename_of_global=function
     VarRef id->id
@@ -65,12 +65,12 @@ let clear_global=function
 (* connection rules *)
 
 let axiom_tac t seq =
-  Proofview.Goal.enter { enter = begin fun gl ->
+  Proofview.Goal.enter begin fun gl ->
   try
     pf_constr_of_global (find_left (project gl) t seq) >>= fun c ->
     exact_no_check c
   with Not_found -> tclFAIL 0 (Pp.str "No axiom link")
-  end }
+  end
 
 let ll_atom_tac a backtrack id continue seq =
   let open EConstr in
@@ -107,7 +107,7 @@ let arrow_tac backtrack continue seq=
 (* left connectives rules *)
 
 let left_and_tac ind backtrack id continue seq =
-  Proofview.Goal.enter { enter = begin fun gl ->
+  Proofview.Goal.enter begin fun gl ->
   let n=(construct_nhyps (pf_env gl) ind).(0) in
    tclIFTHENELSE
      (tclTHENLIST
@@ -116,10 +116,10 @@ let left_and_tac ind backtrack id continue seq =
        tclDO n intro])
      (wrap n false continue seq)
      backtrack
-  end }
+  end
 
 let left_or_tac ind backtrack id continue seq =
-  Proofview.Goal.enter { enter = begin fun gl ->
+  Proofview.Goal.enter begin fun gl ->
   let v=construct_nhyps (pf_env gl) ind in
   let f n=
     tclTHENLIST
@@ -130,7 +130,7 @@ let left_or_tac ind backtrack id continue seq =
       (pf_constr_of_global id >>= simplest_elim)
       (Array.map f v)
       backtrack
-  end }
+  end
 
 let left_false_tac id=
   Tacticals.New.pf_constr_of_global id >>= simplest_elim
@@ -140,7 +140,7 @@ let left_false_tac id=
 (* We use this function for false, and, or, exists *)
 
 let ll_ind_tac (ind,u as indu) largs backtrack id continue seq =
-  Proofview.Goal.enter { enter = begin fun gl ->
+  Proofview.Goal.enter begin fun gl ->
      let rcs=ind_hyps (pf_env gl) (project gl) 0 indu largs in
      let vargs=Array.of_list largs in
              (* construire le terme  H->B, le generaliser etc *)
@@ -161,7 +161,7 @@ let ll_ind_tac (ind,u as indu) largs backtrack id continue seq =
 	       clear_global id;
 	       tclDO lp intro])
 	   (wrap lp false continue seq) backtrack
-  end }
+  end
 
 let ll_arrow_tac a b c backtrack id continue seq=
   let open EConstr in
@@ -199,7 +199,7 @@ let forall_tac backtrack continue seq=
        backtrack)
 
 let left_exists_tac ind backtrack id continue seq =
-  Proofview.Goal.enter { enter = begin fun gl ->
+  Proofview.Goal.enter begin fun gl ->
   let n=(construct_nhyps (pf_env gl) ind).(0) in
     tclIFTHENELSE
       (Tacticals.New.pf_constr_of_global id >>= simplest_elim)
@@ -207,7 +207,7 @@ let left_exists_tac ind backtrack id continue seq =
                     tclDO n intro;
                     (wrap (n-1) false continue seq)])
       backtrack
-  end }
+  end
 
 let ll_forall_tac prod backtrack id continue seq=
   tclORELSE
@@ -215,12 +215,12 @@ let ll_forall_tac prod backtrack id continue seq=
        [tclTHENLIST
 	  [intro;
            (pf_constr_of_global id >>= fun idc ->
-	   Proofview.Goal.enter { enter = begin fun gls->
+	   Proofview.Goal.enter begin fun gls->
               let open EConstr in
 	      let id0 = List.nth (pf_ids_of_hyps gls) 0 in
               let term=mkApp(idc,[|mkVar(id0)|]) in
               tclTHEN (generalize [term]) (clear [id0])
-           end });
+           end);
 	   clear_global id;
 	   intro;
 	   tclCOMPLETE (wrap 1 false continue (deepen seq))];
@@ -239,9 +239,9 @@ let defined_connectives=lazy
    AllOccurrences,EvalConstRef (fst (Term.destConst (constant "iff")))]
 
 let normalize_evaluables=
-  Proofview.Goal.enter { enter = begin fun gl ->
+  Proofview.Goal.enter begin fun gl ->
     unfold_in_concl (Lazy.force defined_connectives) <*>
     tclMAP
       (fun id -> unfold_in_hyp (Lazy.force defined_connectives) (id,InHypTypeOnly))
       (pf_ids_of_hyps gl)
-  end }
+  end