Library Coq.FSets.FMapList


Finite map library

This file proposes an implementation of the non-dependent interface FMapInterface.S using lists of pairs ordered (increasing) with respect to left projection.

Require Import FMapInterface.

Set Implicit Arguments.

Module Raw (X:OrderedType).

Module Import MX := OrderedTypeFacts X.
Module Import PX := KeyOrderedType X.

Definition key := X.t.
Definition t (elt:Type) := list (X.t * elt).

Section Elt.
Variable elt : Type.

Notation eqk := (eqk (elt:=elt)).
Notation eqke := (eqke (elt:=elt)).
Notation ltk := (ltk (elt:=elt)).
Notation MapsTo := (MapsTo (elt:=elt)).
Notation In := (In (elt:=elt)).
Notation Sort := (sort ltk).
Notation Inf := (lelistA (ltk)).

empty


Definition empty : t elt := nil.

Definition Empty m := forall (a : key)(e:elt) , ~ MapsTo a e m.

Lemma empty_1 : Empty empty.
Hint Resolve empty_1.

Lemma empty_sorted : Sort empty.

is_empty


Definition is_empty (l : t elt) : bool := if l then true else false.

Lemma is_empty_1 :forall m, Empty m -> is_empty m = true.

Lemma is_empty_2 : forall m, is_empty m = true -> Empty m.

mem


Function mem (k : key) (s : t elt) {struct s} : bool :=
 match s with
  | nil => false
  | (k',_) :: l =>
     match X.compare k k' with
      | LT _ => false
      | EQ _ => true
      | GT _ => mem k l
     end
 end.

Lemma mem_1 : forall m (Hm:Sort m) x, In x m -> mem x m = true.

Lemma mem_2 : forall m (Hm:Sort m) x, mem x m = true -> In x m.

find


Function find (k:key) (s: t elt) {struct s} : option elt :=
 match s with
  | nil => None
  | (k',x)::s' =>
     match X.compare k k' with
      | LT _ => None
      | EQ _ => Some x
      | GT _ => find k s'
     end
 end.

Lemma find_2 : forall m x e, find x m = Some e -> MapsTo x e m.

Lemma find_1 : forall m (Hm:Sort m) x e, MapsTo x e m -> find x m = Some e.

add


Function add (k : key) (x : elt) (s : t elt) {struct s} : t elt :=
 match s with
  | nil => (k,x) :: nil
  | (k',y) :: l =>
     match X.compare k k' with
      | LT _ => (k,x)::s
      | EQ _ => (k,x)::l
      | GT _ => (k',y) :: add k x l
     end
 end.

Lemma add_1 : forall m x y e, X.eq x y -> MapsTo y e (add x e m).

Lemma add_2 : forall m x y e e',
  ~ X.eq x y -> MapsTo y e m -> MapsTo y e (add x e' m).

Lemma add_3 : forall m x y e e',
  ~ X.eq x y -> MapsTo y e (add x e' m) -> MapsTo y e m.

Lemma add_Inf : forall (m:t elt)(x x':key)(e e':elt),
  Inf (x',e') m -> ltk (x',e') (x,e) -> Inf (x',e') (add x e m).
Hint Resolve add_Inf.

Lemma add_sorted : forall m (Hm:Sort m) x e, Sort (add x e m).

remove


Function remove (k : key) (s : t elt) {struct s} : t elt :=
 match s with
  | nil => nil
  | (k',x) :: l =>
     match X.compare k k' with
      | LT _ => s
      | EQ _ => l
      | GT _ => (k',x) :: remove k l
     end
 end.

Lemma remove_1 : forall m (Hm:Sort m) x y, X.eq x y -> ~ In y (remove x m).

Lemma remove_2 : forall m (Hm:Sort m) x y e,
  ~ X.eq x y -> MapsTo y e m -> MapsTo y e (remove x m).

Lemma remove_3 : forall m (Hm:Sort m) x y e,
  MapsTo y e (remove x m) -> MapsTo y e m.

Lemma remove_Inf : forall (m:t elt)(Hm : Sort m)(x x':key)(e':elt),
  Inf (x',e') m -> Inf (x',e') (remove x m).
Hint Resolve remove_Inf.

Lemma remove_sorted : forall m (Hm:Sort m) x, Sort (remove x m).

elements


Definition elements (m: t elt) := m.

Lemma elements_1 : forall m x e,
  MapsTo x e m -> InA eqke (x,e) (elements m).

Lemma elements_2 : forall m x e,
  InA eqke (x,e) (elements m) -> MapsTo x e m.

Lemma elements_3 : forall m (Hm:Sort m), sort ltk (elements m).

Lemma elements_3w : forall m (Hm:Sort m), NoDupA eqk (elements m).

fold


Function fold (A:Type)(f:key->elt->A->A)(m:t elt) (acc:A) {struct m} : A :=
  match m with
   | nil => acc
   | (k,e)::m' => fold f m' (f k e acc)
  end.

Lemma fold_1 : forall m (A:Type)(i:A)(f:key->elt->A->A),
  fold f m i = fold_left (fun a p => f (fst p) (snd p) a) (elements m) i.

equal


Function equal (cmp:elt->elt->bool)(m m' : t elt) {struct m} : bool :=
  match m, m' with
   | nil, nil => true
   | (x,e)::l, (x',e')::l' =>
      match X.compare x x' with
       | EQ _ => cmp e e' && equal cmp l l'
       | _ => false
      end
   | _, _ => false
  end.

Definition Equivb cmp m m' :=
  (forall k, In k m <-> In k m') /\
  (forall k e e', MapsTo k e m -> MapsTo k e' m' -> cmp e e' = true).

Lemma equal_1 : forall m (Hm:Sort m) m' (Hm': Sort m') cmp,
  Equivb cmp m m' -> equal cmp m m' = true.

Lemma equal_2 : forall m (Hm:Sort m) m' (Hm:Sort m') cmp,
  equal cmp m m' = true -> Equivb cmp m m'.

This lemma isn't part of the spec of Equivb, but is used in FMapAVL

Lemma equal_cons : forall cmp l1 l2 x y, Sort (x::l1) -> Sort (y::l2) ->
  eqk x y -> cmp (snd x) (snd y) = true ->
  (Equivb cmp l1 l2 <-> Equivb cmp (x :: l1) (y :: l2)).

Variable elt':Type.

map and mapi


Fixpoint map (f:elt -> elt') (m:t elt) : t elt' :=
  match m with
   | nil => nil
   | (k,e)::m' => (k,f e) :: map f m'
  end.

Fixpoint mapi (f: key -> elt -> elt') (m:t elt) : t elt' :=
  match m with
   | nil => nil
   | (k,e)::m' => (k,f k e) :: mapi f m'
  end.

End Elt.
Section Elt2.

Variable elt elt' : Type.

Specification of map

Lemma map_1 : forall (m:t elt)(x:key)(e:elt)(f:elt->elt'),
  MapsTo x e m -> MapsTo x (f e) (map f m).

Lemma map_2 : forall (m:t elt)(x:key)(f:elt->elt'),
  In x (map f m) -> In x m.

Lemma map_lelistA : forall (m: t elt)(x:key)(e:elt)(e':elt')(f:elt->elt'),
  lelistA (@ltk elt) (x,e) m ->
  lelistA (@ltk elt') (x,e') (map f m).

Hint Resolve map_lelistA.

Lemma map_sorted : forall (m: t elt)(Hm : sort (@ltk elt) m)(f:elt -> elt'),
  sort (@ltk elt') (map f m).

Specification of mapi

Lemma mapi_1 : forall (m:t elt)(x:key)(e:elt)(f:key->elt->elt'),
  MapsTo x e m ->
  exists y, X.eq y x /\ MapsTo x (f y e) (mapi f m).

Lemma mapi_2 : forall (m:t elt)(x:key)(f:key->elt->elt'),
  In x (mapi f m) -> In x m.

Lemma mapi_lelistA : forall (m: t elt)(x:key)(e:elt)(f:key->elt->elt'),
  lelistA (@ltk elt) (x,e) m ->
  lelistA (@ltk elt') (x,f x e) (mapi f m).

Hint Resolve mapi_lelistA.

Lemma mapi_sorted : forall m (Hm : sort (@ltk elt) m)(f: key ->elt -> elt'),
  sort (@ltk elt') (mapi f m).

End Elt2.
Section Elt3.

map2


Variable elt elt' elt'' : Type.
Variable f : option elt -> option elt' -> option elt''.

Definition option_cons (A:Type)(k:key)(o:option A)(l:list (key*A)) :=
  match o with
   | Some e => (k,e)::l
   | None => l
  end.

Fixpoint map2_l (m : t elt) : t elt'' :=
  match m with
   | nil => nil
   | (k,e)::l => option_cons k (f (Some e) None) (map2_l l)
  end.

Fixpoint map2_r (m' : t elt') : t elt'' :=
  match m' with
   | nil => nil
   | (k,e')::l' => option_cons k (f None (Some e')) (map2_r l')
  end.

Fixpoint map2 (m : t elt) : t elt' -> t elt'' :=
  match m with
   | nil => map2_r
   | (k,e) :: l =>
      fix map2_aux (m' : t elt') : t elt'' :=
        match m' with
         | nil => map2_l m
         | (k',e') :: l' =>
            match X.compare k k' with
             | LT _ => option_cons k (f (Some e) None) (map2 l m')
             | EQ _ => option_cons k (f (Some e) (Some e')) (map2 l l')
             | GT _ => option_cons k' (f None (Some e')) (map2_aux l')
            end
        end
  end.

Notation oee' := (option elt * option elt')%type.

Fixpoint combine (m : t elt) : t elt' -> t oee' :=
  match m with
   | nil => map (fun e' => (None,Some e'))
   | (k,e) :: l =>
      fix combine_aux (m':t elt') : list (key * oee') :=
        match m' with
         | nil => map (fun e => (Some e,None)) m
         | (k',e') :: l' =>
            match X.compare k k' with
             | LT _ => (k,(Some e, None))::combine l m'
             | EQ _ => (k,(Some e, Some e'))::combine l l'
             | GT _ => (k',(None,Some e'))::combine_aux l'
            end
        end
  end.

Definition fold_right_pair (A B C:Type)(f: A->B->C->C)(l:list (A*B))(i:C) :=
  List.fold_right (fun p => f (fst p) (snd p)) i l.

Definition map2_alt m m' :=
  let m0 : t oee' := combine m m' in
  let m1 : t (option elt'') := map (fun p => f (fst p) (snd p)) m0 in
  fold_right_pair (option_cons (A:=elt'')) m1 nil.

Lemma map2_alt_equiv : forall m m', map2_alt m m' = map2 m m'.

Lemma combine_lelistA :
  forall m m' (x:key)(e:elt)(e':elt')(e'':oee'),
  lelistA (@ltk elt) (x,e) m ->
  lelistA (@ltk elt') (x,e') m' ->
  lelistA (@ltk oee') (x,e'') (combine m m').
Hint Resolve combine_lelistA.

Lemma combine_sorted :
  forall m (Hm : sort (@ltk elt) m) m' (Hm' : sort (@ltk elt') m'),
  sort (@ltk oee') (combine m m').

Lemma map2_sorted :
  forall m (Hm : sort (@ltk elt) m) m' (Hm' : sort (@ltk elt') m'),
  sort (@ltk elt'') (map2 m m').

Definition at_least_one (o:option elt)(o':option elt') :=
  match o, o' with
   | None, None => None
   | _, _ => Some (o,o')
  end.

Lemma combine_1 :
  forall m (Hm : sort (@ltk elt) m) m' (Hm' : sort (@ltk elt') m') (x:key),
  find x (combine m m') = at_least_one (find x m) (find x m').

Definition at_least_one_then_f (o:option elt)(o':option elt') :=
  match o, o' with
   | None, None => None
   | _, _ => f o o'
  end.

Lemma map2_0 :
  forall m (Hm : sort (@ltk elt) m) m' (Hm' : sort (@ltk elt') m') (x:key),
  find x (map2 m m') = at_least_one_then_f (find x m) (find x m').

Specification of map2

Lemma map2_1 :
  forall m (Hm : sort (@ltk elt) m) m' (Hm' : sort (@ltk elt') m')(x:key),
  In x m \/ In x m' ->
  find x (map2 m m') = f (find x m) (find x m').

Lemma map2_2 :
  forall m (Hm : sort (@ltk elt) m) m' (Hm' : sort (@ltk elt') m')(x:key),
  In x (map2 m m') -> In x m \/ In x m'.

End Elt3.
End Raw.

Module Make (X: OrderedType) <: S with Module E := X.
Module Raw := Raw X.
Module E := X.

Definition key := E.t.

Record slist (elt:Type) :=
  {this :> Raw.t elt; sorted : sort (@Raw.PX.ltk elt) this}.
Definition t (elt:Type) : Type := slist elt.

Section Elt.
 Variable elt elt' elt'':Type.

 Implicit Types m : t elt.
 Implicit Types x y : key.
 Implicit Types e : elt.

 Definition empty : t elt := Build_slist (Raw.empty_sorted elt).
 Definition is_empty m : bool := Raw.is_empty m.(this).
 Definition add x e m : t elt := Build_slist (Raw.add_sorted m.(sorted) x e).
 Definition find x m : option elt := Raw.find x m.(this).
 Definition remove x m : t elt := Build_slist (Raw.remove_sorted m.(sorted) x).
 Definition mem x m : bool := Raw.mem x m.(this).
 Definition map f m : t elt' := Build_slist (Raw.map_sorted m.(sorted) f).
 Definition mapi (f:key->elt->elt') m : t elt' := Build_slist (Raw.mapi_sorted m.(sorted) f).
 Definition map2 f m (m':t elt') : t elt'' :=
   Build_slist (Raw.map2_sorted f m.(sorted) m'.(sorted)).
 Definition elements m : list (key*elt) := @Raw.elements elt m.(this).
 Definition cardinal m := length m.(this).
 Definition fold (A:Type)(f:key->elt->A->A) m (i:A) : A := @Raw.fold elt A f m.(this) i.
 Definition equal cmp m m' : bool := @Raw.equal elt cmp m.(this) m'.(this).

 Definition MapsTo x e m : Prop := Raw.PX.MapsTo x e m.(this).
 Definition In x m : Prop := Raw.PX.In x m.(this).
 Definition Empty m : Prop := Raw.Empty m.(this).

 Definition Equal m m' := forall y, find y m = find y m'.
 Definition Equiv (eq_elt:elt->elt->Prop) m m' :=
         (forall k, In k m <-> In k m') /\
         (forall k e e', MapsTo k e m -> MapsTo k e' m' -> eq_elt e e').
 Definition Equivb cmp m m' : Prop := @Raw.Equivb elt cmp m.(this) m'.(this).

 Definition eq_key : (key*elt) -> (key*elt) -> Prop := @Raw.PX.eqk elt.
 Definition eq_key_elt : (key*elt) -> (key*elt) -> Prop:= @Raw.PX.eqke elt.
 Definition lt_key : (key*elt) -> (key*elt) -> Prop := @Raw.PX.ltk elt.

 Lemma MapsTo_1 : forall m x y e, E.eq x y -> MapsTo x e m -> MapsTo y e m.

 Lemma mem_1 : forall m x, In x m -> mem x m = true.
 Lemma mem_2 : forall m x, mem x m = true -> In x m.

 Lemma empty_1 : Empty empty.

 Lemma is_empty_1 : forall m, Empty m -> is_empty m = true.
 Lemma is_empty_2 : forall m, is_empty m = true -> Empty m.

 Lemma add_1 : forall m x y e, E.eq x y -> MapsTo y e (add x e m).
 Lemma add_2 : forall m x y e e', ~ E.eq x y -> MapsTo y e m -> MapsTo y e (add x e' m).
 Lemma add_3 : forall m x y e e', ~ E.eq x y -> MapsTo y e (add x e' m) -> MapsTo y e m.

 Lemma remove_1 : forall m x y, E.eq x y -> ~ In y (remove x m).
 Lemma remove_2 : forall m x y e, ~ E.eq x y -> MapsTo y e m -> MapsTo y e (remove x m).
 Lemma remove_3 : forall m x y e, MapsTo y e (remove x m) -> MapsTo y e m.

 Lemma find_1 : forall m x e, MapsTo x e m -> find x m = Some e.
 Lemma find_2 : forall m x e, find x m = Some e -> MapsTo x e m.

 Lemma elements_1 : forall m x e, MapsTo x e m -> InA eq_key_elt (x,e) (elements m).
 Lemma elements_2 : forall m x e, InA eq_key_elt (x,e) (elements m) -> MapsTo x e m.
 Lemma elements_3 : forall m, sort lt_key (elements m).
 Lemma elements_3w : forall m, NoDupA eq_key (elements m).

 Lemma cardinal_1 : forall m, cardinal m = length (elements m).

 Lemma fold_1 : forall m (A : Type) (i : A) (f : key -> elt -> A -> A),
        fold f m i = fold_left (fun a p => f (fst p) (snd p) a) (elements m) i.

 Lemma equal_1 : forall m m' cmp, Equivb cmp m m' -> equal cmp m m' = true.
 Lemma equal_2 : forall m m' cmp, equal cmp m m' = true -> Equivb cmp m m'.

 End Elt.

 Lemma map_1 : forall (elt elt':Type)(m: t elt)(x:key)(e:elt)(f:elt->elt'),
        MapsTo x e m -> MapsTo x (f e) (map f m).
 Lemma map_2 : forall (elt elt':Type)(m: t elt)(x:key)(f:elt->elt'),
        In x (map f m) -> In x m.

 Lemma mapi_1 : forall (elt elt':Type)(m: t elt)(x:key)(e:elt)
        (f:key->elt->elt'), MapsTo x e m ->
        exists y, E.eq y x /\ MapsTo x (f y e) (mapi f m).
 Lemma mapi_2 : forall (elt elt':Type)(m: t elt)(x:key)
        (f:key->elt->elt'), In x (mapi f m) -> In x m.

 Lemma map2_1 : forall (elt elt' elt'':Type)(m: t elt)(m': t elt')
        (x:key)(f:option elt->option elt'->option elt''),
        In x m \/ In x m' ->
        find x (map2 f m m') = f (find x m) (find x m').
 Lemma map2_2 : forall (elt elt' elt'':Type)(m: t elt)(m': t elt')
        (x:key)(f:option elt->option elt'->option elt''),
        In x (map2 f m m') -> In x m \/ In x m'.

End Make.

Module Make_ord (X: OrderedType)(D : OrderedType) <:
Sord with Module Data := D
        with Module MapS.E := X.

Module Data := D.
Module MapS := Make(X).
Import MapS.

Module MD := OrderedTypeFacts(D).
Import MD.

Definition t := MapS.t D.t.

Definition cmp e e' := match D.compare e e' with EQ _ => true | _ => false end.

Fixpoint eq_list (m m' : list (X.t * D.t)) : Prop :=
  match m, m' with
   | nil, nil => True
   | (x,e)::l, (x',e')::l' =>
      match X.compare x x' with
       | EQ _ => D.eq e e' /\ eq_list l l'
       | _ => False
      end
   | _, _ => False
  end.

Definition eq m m' := eq_list m.(this) m'.(this).

Fixpoint lt_list (m m' : list (X.t * D.t)) : Prop :=
  match m, m' with
   | nil, nil => False
   | nil, _ => True
   | _, nil => False
   | (x,e)::l, (x',e')::l' =>
      match X.compare x x' with
       | LT _ => True
       | GT _ => False
       | EQ _ => D.lt e e' \/ (D.eq e e' /\ lt_list l l')
      end
  end.

Definition lt m m' := lt_list m.(this) m'.(this).

Lemma eq_equal : forall m m', eq m m' <-> equal cmp m m' = true.

Lemma eq_1 : forall m m', Equivb cmp m m' -> eq m m'.

Lemma eq_2 : forall m m', eq m m' -> Equivb cmp m m'.

Lemma eq_refl : forall m : t, eq m m.

Lemma eq_sym : forall m1 m2 : t, eq m1 m2 -> eq m2 m1.

Lemma eq_trans : forall m1 m2 m3 : t, eq m1 m2 -> eq m2 m3 -> eq m1 m3.

Lemma lt_trans : forall m1 m2 m3 : t, lt m1 m2 -> lt m2 m3 -> lt m1 m3.

Lemma lt_not_eq : forall m1 m2 : t, lt m1 m2 -> ~ eq m1 m2.

Ltac cmp_solve := unfold eq, lt; simpl; try Raw.MX.elim_comp; auto.

Definition compare : forall m1 m2, Compare lt eq m1 m2.

End Make_ord.