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, 4 insertions, 6 deletions

diff --git a/tactics/tactics.mli b/tactics/tactics.mli
index 0dbcce02c..ec8fe1145 100644
--- a/tactics/tactics.mli
+++ b/tactics/tactics.mli
@@ -29,7 +29,7 @@ open Locus
 
 (** {6 General functions. } *)
 
-val is_quantified_hypothesis : Id.t -> ('a, 'r) Proofview.Goal.t -> bool
+val is_quantified_hypothesis : Id.t -> 'a Proofview.Goal.t -> bool
 
 (** {6 Primitive tactics. } *)
 
@@ -75,7 +75,7 @@ val intros               : unit Proofview.tactic
 (** [depth_of_quantified_hypothesis b h g] returns the index of [h] in
    the conclusion of goal [g], up to head-reduction if [b] is [true] *)
 val depth_of_quantified_hypothesis :
-  bool -> quantified_hypothesis -> ('a, 'r) Proofview.Goal.t -> int
+  bool -> quantified_hypothesis -> 'a Proofview.Goal.t -> int
 
 val intros_until         : quantified_hypothesis -> unit Proofview.tactic
 
@@ -131,7 +131,7 @@ val exact_proof      : Constrexpr.constr_expr -> unit Proofview.tactic
 
 type tactic_reduction = env -> evar_map -> constr -> constr
 
-type change_arg = patvar_map -> constr Sigma.run
+type change_arg = patvar_map -> evar_map -> evar_map * constr
 
 val make_change_arg   : constr -> change_arg
 val reduct_in_hyp     : ?check:bool -> tactic_reduction -> hyp_location -> unit Proofview.tactic
@@ -211,8 +211,6 @@ val apply_delayed_in :
     (clear_flag * delayed_open_constr_with_bindings located) list ->
     intro_pattern option -> unit Proofview.tactic
 
-val run_delayed : Environ.env -> evar_map -> 'a delayed_open -> 'a * evar_map
-
 (** {6 Elimination tactics. } *)
 
 (*
@@ -437,7 +435,7 @@ end
 
 module New : sig
 
-  val refine : ?unsafe:bool -> constr Sigma.run -> unit Proofview.tactic
+  val refine : ?unsafe:bool -> (evar_map -> evar_map * constr) -> unit Proofview.tactic
   (** [refine ?unsafe c] is [Refine.refine ?unsafe c]
       followed by beta-iota-reduction of the conclusion. *)