From 954fbd3b102060ed1e2122f571a430f05a174e42 Mon Sep 17 00:00:00 2001
From: Maxime Dénès
Date: Tue, 9 May 2017 22:14:35 +0200
Subject: 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.
---
 plugins/ltac/pptactic.ml | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

(limited to 'plugins/ltac/pptactic.ml')

diff --git a/plugins/ltac/pptactic.ml b/plugins/ltac/pptactic.ml
index 9029858279..9446f9df4d 100644
--- a/plugins/ltac/pptactic.ml
+++ b/plugins/ltac/pptactic.ml
@@ -1179,11 +1179,10 @@ let declare_extra_genarg_pprule wit
 
 (** Registering *)
 
-let run_delayed c =
-  Sigma.run Evd.empty { Sigma.run = fun sigma -> c.delayed (Global.env ()) sigma }
+let run_delayed c = c (Global.env ()) Evd.empty
 
 let run_delayed_destruction_arg = function (* HH: Using Evd.empty looks suspicious *)
-  | clear_flag,ElimOnConstr g -> clear_flag,ElimOnConstr (fst (run_delayed g))
+  | clear_flag,ElimOnConstr g -> clear_flag,ElimOnConstr (snd (run_delayed g))
   | clear_flag,ElimOnAnonHyp n as x -> x
   | clear_flag,ElimOnIdent id as x -> x
 
@@ -1203,7 +1202,7 @@ let () =
     wit_intro_pattern
     (Miscprint.pr_intro_pattern pr_constr_expr)
     (Miscprint.pr_intro_pattern (fun (c,_) -> pr_glob_constr c))
-    (Miscprint.pr_intro_pattern (fun c -> pr_econstr (fst (run_delayed c))));
+    (Miscprint.pr_intro_pattern (fun c -> pr_econstr (snd (run_delayed c))));
   Genprint.register_print0
     wit_clause_dft_concl
     (pr_clauses (Some true) pr_lident)
@@ -1236,11 +1235,11 @@ let () =
   Genprint.register_print0 wit_bindings
     (Miscprint.pr_bindings_no_with pr_constr_expr pr_lconstr_expr)
     (Miscprint.pr_bindings_no_with (pr_and_constr_expr pr_glob_constr) (pr_and_constr_expr pr_lglob_constr))
-    (fun it -> Miscprint.pr_bindings_no_with pr_econstr pr_leconstr (fst (run_delayed it)));
+    (fun it -> Miscprint.pr_bindings_no_with pr_econstr pr_leconstr (snd (run_delayed it)));
   Genprint.register_print0 wit_constr_with_bindings
     (pr_with_bindings pr_constr_expr pr_lconstr_expr)
     (pr_with_bindings (pr_and_constr_expr pr_glob_constr) (pr_and_constr_expr pr_lglob_constr))
-    (fun it -> pr_with_bindings pr_econstr pr_leconstr (fst (run_delayed it)));
+    (fun it -> pr_with_bindings pr_econstr pr_leconstr (snd (run_delayed it)));
   Genprint.register_print0 Tacarg.wit_destruction_arg
     (pr_destruction_arg pr_constr_expr pr_lconstr_expr)
     (pr_destruction_arg (pr_and_constr_expr pr_glob_constr) (pr_and_constr_expr pr_lglob_constr))
-- 
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