Primitive persistent arrays

Persistent arrays expose a functional interface but are implemented
using an imperative data structure. The OCaml implementation is based on
Jean-Christophe Filliâtre's.

Co-authored-by: Benjamin Grégoire <Benjamin.Gregoire@inria.fr>
Co-authored-by: Gaëtan Gilbert <gaetan.gilbert@skyskimmer.net>

7 files changed, 42 insertions, 5 deletions

diff --git a/interp/constrexpr.ml b/interp/constrexpr.ml
index 9c4b78f4ed..c98e05370e 100644
--- a/interp/constrexpr.ml
+++ b/interp/constrexpr.ml
@@ -115,6 +115,7 @@ and constr_expr_r =
   | CGeneralization of Glob_term.binding_kind * abstraction_kind option * constr_expr
   | CPrim of prim_token
   | CDelimiters of string * constr_expr
+  | CArray of instance_expr option * constr_expr array * constr_expr * constr_expr
 and constr_expr = constr_expr_r CAst.t
 
 and case_expr = constr_expr                 (* expression that is being matched *)
diff --git a/interp/constrexpr_ops.ml b/interp/constrexpr_ops.ml
index 3d99e1d227..ce8e7d3c2c 100644
--- a/interp/constrexpr_ops.ml
+++ b/interp/constrexpr_ops.ml
@@ -174,10 +174,14 @@ let rec constr_expr_eq e1 e2 =
     | CDelimiters(s1,e1), CDelimiters(s2,e2) ->
       String.equal s1 s2 &&
       constr_expr_eq e1 e2
+    | CArray(u1,t1,def1,ty1), CArray(u2,t2,def2,ty2) ->
+      Array.equal constr_expr_eq t1 t2 &&
+      constr_expr_eq def1 def2 && constr_expr_eq ty1 ty2 &&
+      eq_universes u1 u2
   | (CRef _ | CFix _ | CCoFix _ | CProdN _ | CLambdaN _ | CLetIn _ | CAppExpl _
      | CApp _ | CRecord _ | CCases _ | CLetTuple _ | CIf _ | CHole _
      | CPatVar _ | CEvar _ | CSort _ | CCast _ | CNotation _ | CPrim _
-     | CGeneralization _ | CDelimiters _ ), _ -> false
+     | CGeneralization _ | CDelimiters _ | CArray _), _ -> false
 
 and args_eq (a1,e1) (a2,e2) =
   Option.equal (eq_ast explicitation_eq) e1 e2 &&
@@ -353,6 +357,7 @@ let fold_constr_expr_with_binders g f n acc = CAst.with_val (function
             (fold_local_binders g f n acc t lb) c lb) l acc
     | CCoFix (_,_) ->
       Feedback.msg_warning (strbrk "Capture check in multiple binders not done"); acc
+    | CArray (_u,t,def,ty) -> f n (f n (Array.fold_left (f n) acc t) def) ty
   )
 
 let free_vars_of_constr_expr c =
@@ -439,6 +444,8 @@ let map_constr_expr_with_binders g f e = CAst.map (function
           let e'' = List.fold_left (fun e ({ CAst.v = id },_,_,_) -> g id e) e' dl in
           let d' = f e'' d in
           (id,bl',t',d')) dl)
+    | CArray (u, t, def, ty) ->
+      CArray (u, Array.map (f e) t, f e def, f e ty)
   )
 
 (* Used in constrintern *)
diff --git a/interp/constrextern.ml b/interp/constrextern.ml
index b087431e85..95df626d4c 100644
--- a/interp/constrextern.ml
+++ b/interp/constrextern.ml
@@ -1095,6 +1095,9 @@ let rec extern inctx ?impargs scopes vars r =
 
   | GFloat f -> extern_float f (snd scopes)
 
+  | GArray(u,t,def,ty) ->
+    CArray(u,Array.map (extern inctx scopes vars) t, extern inctx scopes vars def, extern_typ scopes vars ty)
+
   in insert_entry_coercion coercion (CAst.make ?loc c)
 
 and extern_typ ?impargs (subentry,(_,scopes)) =
@@ -1469,6 +1472,9 @@ let rec glob_of_pat avoid env sigma pat = DAst.make @@ match pat with
   | PSort Sorts.InType -> GSort (UAnonymous {rigid=true})
   | PInt i -> GInt i
   | PFloat f -> GFloat f
+  | PArray(t,def,ty) ->
+    let glob_of = glob_of_pat avoid env sigma in
+    GArray (None, Array.map glob_of t, glob_of def, glob_of ty)
 
 let extern_constr_pattern env sigma pat =
   extern true (InConstrEntrySomeLevel,(None,[])) Id.Set.empty (glob_of_pat Id.Set.empty env sigma pat)
diff --git a/interp/constrintern.ml b/interp/constrintern.ml
index d95554de56..987aa63392 100644
--- a/interp/constrintern.ml
+++ b/interp/constrintern.ml
@@ -772,7 +772,7 @@ let rec adjust_env env = function
   | NCast (c,_) -> adjust_env env c
   | NApp _ -> restart_no_binders env
   | NVar _ | NRef _ | NHole _ | NCases _ | NLetTuple _ | NIf _
-  | NRec _ | NSort _ | NInt _ | NFloat _
+  | NRec _ | NSort _ | NInt _ | NFloat _ | NArray _
   | NList _ | NBinderList _ -> env (* to be safe, but restart should be ok *)
 
 let instantiate_notation_constr loc intern intern_pat ntnvars subst infos c =
@@ -2204,6 +2204,8 @@ let internalize globalenv env pattern_mode (_, ntnvars as lvar) c =
     | CCast (c1, c2) ->
         DAst.make ?loc @@
         GCast (intern env c1, map_cast_type (intern_type (slide_binders env)) c2)
+    | CArray(u,t,def,ty) ->
+      DAst.make ?loc @@ GArray(u, Array.map (intern env) t, intern env def, intern env ty)
     )
   and intern_type env = intern (set_type_scope env)
 
diff --git a/interp/impargs.ml b/interp/impargs.ml
index c6405b40fc..db102470b0 100644
--- a/interp/impargs.ml
+++ b/interp/impargs.ml
@@ -236,7 +236,7 @@ let rec is_rigid_head sigma t = match kind sigma t with
         | Fix ((fi,i),_) -> is_rigid_head sigma (args.(fi.(i)))
         | _ -> is_rigid_head sigma f)
   | Lambda _ | LetIn _ | Construct _ | CoFix _ | Fix _
-  | Prod _ | Meta _ | Cast _ | Int _ | Float _ -> assert false
+  | Prod _ | Meta _ | Cast _ | Int _ | Float _ | Array _ -> assert false
 
 let is_rigid env sigma t =
   let open Context.Rel.Declaration in
diff --git a/interp/notation_ops.ml b/interp/notation_ops.ml
index 54065e8b35..6422e184b5 100644
--- a/interp/notation_ops.ml
+++ b/interp/notation_ops.ml
@@ -92,9 +92,12 @@ let rec eq_notation_constr (vars1,vars2 as vars) t1 t2 = match t1, t2 with
    Uint63.equal i1 i2
 | NFloat f1, NFloat f2 ->
   Float64.equal f1 f2
+| NArray(t1,def1,ty1), NArray(t2,def2,ty2) ->
+  Array.equal (eq_notation_constr vars) t1 t2 && (eq_notation_constr vars) def1 def2
+    && eq_notation_constr vars ty1 ty2
 | (NRef _ | NVar _ | NApp _ | NHole _ | NList _ | NLambda _ | NProd _
   | NBinderList _ | NLetIn _ | NCases _ | NLetTuple _ | NIf _
-  | NRec _ | NSort _ | NCast _ | NInt _ | NFloat _), _ -> false
+  | NRec _ | NSort _ | NCast _ | NInt _ | NFloat _ | NArray _), _ -> false
 
 (**********************************************************************)
 (* Re-interpret a notation as a glob_constr, taking care of binders   *)
@@ -249,6 +252,7 @@ let glob_constr_of_notation_constr_with_binders ?loc g f ?(h=default_binder_stat
   | NRef x -> GRef (x,None)
   | NInt i -> GInt i
   | NFloat f -> GFloat f
+  | NArray (t,def,ty) -> GArray(None, Array.map (f e) t, f e def, f e ty)
 
 let glob_constr_of_notation_constr ?loc x =
   let rec aux () x =
@@ -472,6 +476,7 @@ let notation_constr_and_vars_of_glob_constr recvars a =
      if arg != None then has_ltac := true;
      NHole (w, naming, arg)
   | GRef (r,_) -> NRef r
+  | GArray (_u,t,def,ty) -> NArray (Array.map aux t, aux def, aux ty)
   | GEvar _ | GPatVar _ ->
       user_err Pp.(str "Existential variables not allowed in notations.")
   ) x
@@ -675,6 +680,14 @@ let rec subst_notation_constr subst bound raw =
       let k' = smartmap_cast_type (subst_notation_constr subst bound) k in
       if r1' == r1 && k' == k then raw else NCast(r1',k')
 
+  | NArray (t,def,ty) ->
+      let def' = subst_notation_constr subst bound def
+      and t' = Array.Smart.map (subst_notation_constr subst bound) t
+      and ty' = subst_notation_constr subst bound ty
+      in
+        if def' == def && t' == t && ty' == ty then raw else
+          NArray(t',def',ty')
+
 let subst_interpretation subst (metas,pat) =
   let bound = List.fold_left (fun accu (id, _) -> Id.Set.add id accu) Id.Set.empty metas in
   (metas,subst_notation_constr subst bound pat)
@@ -1254,9 +1267,16 @@ let rec match_ inner u alp metas sigma a1 a2 =
           match_names metas (alp,sigma) (Name id') na in
       match_in u alp metas sigma (mkGApp a1 [DAst.make @@ GVar id']) b2
 
+  | GArray(_u,t,def,ty), NArray(nt,ndef,nty) ->
+    if Int.equal (Array.length t) (Array.length nt) then
+      let sigma = match_in u alp metas sigma def ndef in
+      let sigma = match_in u alp metas sigma ty nty in
+      Array.fold_left2 (match_in u alp metas) sigma t nt
+    else raise No_match
+
   | (GRef _ | GVar _ | GEvar _ | GPatVar _ | GApp _ | GLambda _ | GProd _
      | GLetIn _ | GCases _ | GLetTuple _ | GIf _ | GRec _ | GSort _ | GHole _
-     | GCast _ | GInt _ | GFloat _), _ -> raise No_match
+     | GCast _ | GInt _ | GFloat _ | GArray _), _ -> raise No_match
 
 and match_in u = match_ true u
 
diff --git a/interp/notation_term.ml b/interp/notation_term.ml
index 4e9b8bbb17..82238b71b7 100644
--- a/interp/notation_term.ml
+++ b/interp/notation_term.ml
@@ -45,6 +45,7 @@ type notation_constr =
   | NCast of notation_constr * notation_constr cast_type
   | NInt of Uint63.t
   | NFloat of Float64.t
+  | NArray of notation_constr array * notation_constr * notation_constr
 
 (** Note concerning NList: first constr is iterator, second is terminator;
     first id is where each argument of the list has to be substituted