Moving some universe substitution code out of the kernel.

This code was not used at all inside the kernel, it was related to universe
unification that happens in the upper layer. It makes more sense to put it
somewhere upper.

1 files changed, 74 insertions, 4 deletions

diff --git a/engine/universes.ml b/engine/universes.ml
index 30490ec56..eaddf98a8 100644
--- a/engine/universes.ml
+++ b/engine/universes.ml
@@ -181,6 +181,30 @@ let enforce_eq_instances_univs strict x y c =
       (fun x y -> Constraints.add (Universe.make x, d, Universe.make y))
       ax ay c
 
+let enforce_univ_constraint (u,d,v) =
+  match d with
+  | Eq -> enforce_eq u v
+  | Le -> enforce_leq u v
+  | Lt -> enforce_leq (super u) v
+
+let subst_univs_level fn l =
+  try Some (fn l)
+  with Not_found -> None
+
+let subst_univs_constraint fn (u,d,v as c) cstrs =
+  let u' = subst_univs_level fn u in
+  let v' = subst_univs_level fn v in
+  match u', v' with
+  | None, None -> Constraint.add c cstrs
+  | Some u, None -> enforce_univ_constraint (u,d,Universe.make v) cstrs
+  | None, Some v -> enforce_univ_constraint (Universe.make u,d,v) cstrs
+  | Some u, Some v -> enforce_univ_constraint (u,d,v) cstrs
+
+let subst_univs_constraints subst csts =
+  Constraint.fold
+    (fun c cstrs -> subst_univs_constraint subst c cstrs)
+    csts Constraint.empty
+
 let subst_univs_universe_constraint fn (u,d,v) =
   let u' = subst_univs_universe fn u and v' = subst_univs_universe fn v in
     if Universe.equal u' v' then None
@@ -519,13 +543,60 @@ let choose_canonical ctx flexible algs s =
 	      let canon = LSet.choose algs in
 		canon, (global, rigid, LSet.remove canon flexible)
 
+let level_subst_of f =
+  fun l ->
+    try let u = f l in
+          match Universe.level u with
+          | None -> l
+          | Some l -> l
+    with Not_found -> l
+
+let subst_univs_fn_constr f c =
+  let changed = ref false in
+  let fu = Univ.subst_univs_universe f in
+  let fi = Univ.Instance.subst_fn (level_subst_of f) in
+  let rec aux t =
+    match kind t with
+    | Sort (Sorts.Type u) ->
+      let u' = fu u in
+        if u' == u then t else
+          (changed := true; mkSort (Sorts.sort_of_univ u'))
+    | Const (c, u) ->
+      let u' = fi u in
+        if u' == u then t
+        else (changed := true; mkConstU (c, u'))
+    | Ind (i, u) ->
+      let u' = fi u in
+        if u' == u then t
+        else (changed := true; mkIndU (i, u'))
+    | Construct (c, u) ->
+      let u' = fi u in
+        if u' == u then t
+        else (changed := true; mkConstructU (c, u'))
+    | _ -> map aux t
+  in
+  let c' = aux c in
+    if !changed then c' else c
+
+let subst_univs_constr subst c =
+  if Univ.is_empty_subst subst then c
+  else
+    let f = Univ.make_subst subst in
+      subst_univs_fn_constr f c
+
+let subst_univs_constr =
+  if Flags.profile then
+    let subst_univs_constr_key = CProfile.declare_profile "subst_univs_constr" in
+      CProfile.profile2 subst_univs_constr_key subst_univs_constr
+  else subst_univs_constr
+
 let subst_univs_fn_puniverses lsubst (c, u as cu) =
   let u' = Instance.subst_fn lsubst u in
     if u' == u then cu else (c, u')
 
 let nf_evars_and_universes_opt_subst f subst =
   let subst = fun l -> match LMap.find l subst with None -> raise Not_found | Some l' -> l' in
-  let lsubst = Univ.level_subst_of subst in
+  let lsubst = level_subst_of subst in
   let rec aux c =
     match kind c with
     | Evar (evk, args) ->
@@ -605,7 +676,7 @@ let normalize_opt_subst ctx =
   in !ectx
 
 type universe_opt_subst = Universe.t option universe_map
-	  
+
 let make_opt_subst s = 
   fun x -> 
     (match Univ.LMap.find x s with
@@ -614,8 +685,7 @@ let make_opt_subst s =
 
 let subst_opt_univs_constr s = 
   let f = make_opt_subst s in
-    Vars.subst_univs_fn_constr f
-
+  subst_univs_fn_constr f
 
 let normalize_univ_variables ctx = 
   let ctx = normalize_opt_subst ctx in