(* Copyright 2015 IMDEA Software Institute Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. *)
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(* This file contains an implementation of maps over non-zero natural         *)
(* numbers, pcm instance for natmap, gapless natmaps, natmaps with binary     *)
(* range, several sorts of continuous natmaps.                                *)
(* Histories are a special case of natmaps.                                   *)
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Set Implicit Arguments.
Unset Strict Implicit.
Unset Printing Implicit Defensive.
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(* Maps over non-0 nats *)
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Module Type NMSig.
Parameter tp : Type -> Type.
Section Params.
Variable A : Type.
Notation tp := (tp A).
Parameter nm_undef : tp.
Parameter defined : tp -> bool.
Parameter empty : tp.
Parameter upd : nat -> A -> tp -> tp.
Parameter dom : tp -> seq nat.
Parameter dom_eq : tp -> tp -> bool.
Parameter free : nat -> tp -> tp.
Parameter find : nat -> tp -> option A.
Parameter union : tp -> tp -> tp.
Parameter nm_filter : pred nat -> tp -> tp.
Parameter empb : tp -> bool.
Parameter undefb : tp -> bool.
Parameter pts : nat -> A -> tp.
Parameter from : tp -> @UM.base nat_ordType A (fun x => x != 0).
Parameter to : @UM.base nat_ordType A (fun x => x != 0) -> tp.

Axiom unionE : forall f1 f2, union f1 f2 = to (UM.union (from f1) (from f2)).