extmap.mli 12.6 KB
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(***********************************************************************)
(*                                                                     *)
(*                           Objective Caml                            *)
(*                                                                     *)
(*            Xavier Leroy, projet Cristal, INRIA Rocquencourt         *)
(*                                                                     *)
(*  Copyright 1996 Institut National de Recherche en Informatique et   *)
(*  en Automatique.  All rights reserved.  This file is distributed    *)
(*  under the terms of the GNU Library General Public License, with    *)
(*  the special exception on linking described in file ../LICENSE.     *)
(*                                                                     *)
(***********************************************************************)

(* This file originates from the OCaml v 3.12 Standard Library.
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   It was extended and modified for the needs of the Why3 project.
   It is distributed under the terms of its initial license, which
   is provided in the file OCAML-LICENSE. *)
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  (** Association tables over ordered types.

     This module implements applicative association tables, also known as
     finite maps or dictionaries, given a total ordering function
     over the keys.
     All operations over maps are purely applicative (no side-effects).
     The implementation uses balanced binary trees, and therefore searching
     and insertion take time logarithmic in the size of the map.
  *)

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  (** Input signature of the functor {!Extmap.Make}. *)
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  module type OrderedType = Map.OrderedType

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  (** Output signature of the functor {!Extmap.Make}. *)
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  module type S =
  sig
    type key
    (** The type of the map keys. *)

    type (+'a) t
    (** The type of maps from type [key] to type ['a]. *)

    val empty: 'a t
    (** The empty map. *)

    val is_empty: 'a t -> bool
    (** Test whether a map is empty or not. *)

    val mem: key -> 'a t -> bool
    (** [mem x m] returns [true] if [m] contains a binding for [x],
        and [false] otherwise. *)

    val add: key -> 'a -> 'a t -> 'a t
    (** [add x y m] returns a map containing the same bindings as
        [m], plus a binding of [x] to [y]. If [x] was already bound
        in [m], its previous binding disappears. *)

    val singleton: key -> 'a -> 'a t
    (** [singleton x y] returns the one-element map that contains a binding [y]
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        for [x]. *)
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    val remove: key -> 'a t -> 'a t
    (** [remove x m] returns a map containing the same bindings as
        [m], except for [x] which is unbound in the returned map. *)

    val merge:
         (key -> 'a option -> 'b option -> 'c option) -> 'a t -> 'b t -> 'c t
    (** [merge f m1 m2] computes a map whose keys is a subset of keys of [m1]
        and of [m2]. The presence of each such binding, and the corresponding
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        value, is determined with the function [f]. *)
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    val compare: ('a -> 'a -> int) -> 'a t -> 'a t -> int
    (** Total ordering between maps.  The first argument is a total ordering
        used to compare data associated with equal keys in the two maps. *)

    val equal: ('a -> 'a -> bool) -> 'a t -> 'a t -> bool
    (** [equal cmp m1 m2] tests whether the maps [m1] and [m2] are
        equal, that is, contain equal keys and associate them with
        equal data.  [cmp] is the equality predicate used to compare
        the data associated with the keys. *)

    val iter: (key -> 'a -> unit) -> 'a t -> unit
    (** [iter f m] applies [f] to all bindings in map [m].
       [f] receives the key as first argument, and the associated value
       as second argument.  The bindings are passed to [f] in increasing
       order with respect to the ordering over the type of the keys. *)

    val fold: (key -> 'a -> 'b -> 'b) -> 'a t -> 'b -> 'b
    (** [fold f m a] computes [(f kN dN ... (f k1 d1 a)...)], where
        [k1 ... kN] are the keys of all bindings in [m] (in increasing
        order), and [d1 ... dN] are the associated data. *)

    val for_all: (key -> 'a -> bool) -> 'a t -> bool
    (** [for_all p m] checks if all the bindings of the map
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        satisfy the predicate [p]. *)
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    val exists: (key -> 'a -> bool) -> 'a t -> bool
    (** [exists p m] checks if at least one binding of the map
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        satisfy the predicate [p]. *)
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    val filter: (key -> 'a -> bool) -> 'a t -> 'a t
    (** [filter p m] returns the map with all the bindings in [m]
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        that satisfy predicate [p]. *)
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    val partition: (key -> 'a -> bool) -> 'a t -> 'a t * 'a t
    (** [partition p m] returns a pair of maps [(m1, m2)], where
        [m1] contains all the bindings of [s] that satisfy the
        predicate [p], and [m2] is the map with all the bindings of
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        [s] that do not satisfy [p]. *)
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    val cardinal: 'a t -> int
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    (** Return the number of bindings of a map. *)
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    val bindings: 'a t -> (key * 'a) list
    (** Return the list of all bindings of the given map.
        The returned list is sorted in increasing order with respect
        to the ordering [Ord.compare], where [Ord] is the argument
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        given to {!Extmap.Make}. *)
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    val min_binding: 'a t -> (key * 'a)
    (** Return the smallest binding of the given map
        (with respect to the [Ord.compare] ordering), or raise
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        [Not_found] if the map is empty. *)
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    val max_binding: 'a t -> (key * 'a)
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    (** Same as {!Extmap.S.min_binding}, but returns the largest
        binding of the given map. *)
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    val choose: 'a t -> (key * 'a)
    (** Return one binding of the given map, or raise [Not_found] if
        the map is empty. Which binding is chosen is unspecified,
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        but equal bindings will be chosen for equal maps. *)
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    val split: key -> 'a t -> 'a t * 'a option * 'a t
    (** [split x m] returns a triple [(l, data, r)], where
          [l] is the map with all the bindings of [m] whose key
        is strictly less than [x];
          [r] is the map with all the bindings of [m] whose key
        is strictly greater than [x];
          [data] is [None] if [m] contains no binding for [x],
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          or [Some v] if [m] binds [v] to [x]. *)
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    val find: key -> 'a t -> 'a
    (** [find x m] returns the current binding of [x] in [m],
        or raises [Not_found] if no such binding exists. *)

    val map: ('a -> 'b) -> 'a t -> 'b t
    (** [map f m] returns a map with same domain as [m], where
        the associated value [a] of all bindings of [m] has been
        replaced by the result of the application of [f] to [a].
        The bindings are passed to [f] in increasing order
        with respect to the ordering over the type of the keys. *)

    val mapi: (key -> 'a -> 'b) -> 'a t -> 'b t
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    (** Same as {!Extmap.S.map}, but the function receives as arguments both
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        the key and the associated value for each binding of the map. *)

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    (** @Added in Why3 *)
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    val is_num_elt : int -> 'a t -> bool
    (** check if the map has the given number of elements *)

    val change : ('a option -> 'a option) -> key -> 'a t -> 'a t
    (** [change f x m] returns a map containing the same bindings as
        [m], except the binding of [x] in [m] is changed from [y] to
        [f (Some y)] if [m] contains a binding of [x], otherwise the
        binding of [x] becomes [f None].

        [change f x m] corresponds to a more efficient way to do
        [match (try f (Some (find x m)) with Not_found -> f None) with
          | None -> m
          | Some v -> add x v] *)

    val union : (key -> 'a -> 'a -> 'a option) -> 'a t -> 'a t -> 'a t
    (** [union f m1 m2] computes a map whose keys is a subset of keys
        of [m1] and of [m2]. If a binding is present in [m1] (resp. [m2])
        and not in [m2] (resp. [m1]) the same binding is present in
        the result. The function [f] is called only in ambiguous cases. *)

    val inter : (key -> 'a -> 'b -> 'c option) -> 'a t -> 'b t -> 'c t
    (** [inter f m1 m2] computes a map whose keys is a subset of
        the intersection of keys of [m1] and of [m2]. *)

    val diff : (key -> 'a -> 'b -> 'a option) -> 'a t -> 'b t -> 'a t
    (** [diff f m1 m2] computes a map whose keys is a subset of keys
        of [m1]. [f] is applied on key which belongs to [m1] and [m2]
        if [f] returns [None] the binding is removed from [m1],
        otherwise [Some d1] is returned, the key binds to [d1] in [m1] *)

    val submap : (key -> 'a -> 'b -> bool) -> 'a t -> 'b t -> bool
    (** [submap pr m1 m2] verifies that all the keys in m1 are in m2
        and that for each such binding pr is verified. *)

    val disjoint : (key -> 'a -> 'b -> bool) -> 'a t -> 'b t -> bool
    (** [disjoint pr m1 m2] verifies that for every common key in m1
        and m2, pr is verified. *)

    val set_union : 'a t -> 'a t -> 'a t
    (** [set_union = union (fun _ x _ -> Some x)] *)

    val set_inter : 'a t -> 'b t -> 'a t
    (** [set_inter = inter (fun _ x _ -> Some x)] *)

    val set_diff : 'a t -> 'b t -> 'a t
    (** [set_diff = diff (fun _ _ _ -> None)] *)

    val set_submap : 'a t -> 'b t -> bool
    (** [set_submap = submap (fun _ _ _ -> true)] *)

    val set_disjoint : 'a t -> 'b t -> bool
    (** [set_disjoint = disjoint (fun _ _ _ -> false)] *)

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    val set_compare : 'a t -> 'b t -> int
    (** [set_compare = compare (fun _ _ -> 0)] *)

    val set_equal : 'a t -> 'b t -> bool
    (** [set_equal = equal (fun _ _ -> true)] *)

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    val find_def : 'a -> key -> 'a t -> 'a
    (** [find_def x d m] returns the current binding of [x] in [m],
        or return [d] if no such binding exists. *)

    val find_opt : key -> 'a t -> 'a option
    (** [find_opt x m] returns the [Some] of the current binding
        of [x] in [m], or return [None] if no such binding exists. *)

    val find_exn : exn -> key -> 'a t -> 'a
    (** [find_exn exn x d m] returns the current binding
        of [x] in [m], or raise [exn] if no such binding exists. *)

    val map_filter: ('a -> 'b option) -> 'a t -> 'b t
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    (** Same as {!Extmap.S.map}, but may remove bindings. *)
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    val mapi_filter: (key -> 'a -> 'b option) -> 'a t -> 'b t
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    (** Same as {!Extmap.S.mapi}, but may remove bindings. *)
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    val mapi_fold:
      (key -> 'a -> 'acc -> 'acc * 'b) -> 'a t -> 'acc -> 'acc * 'b t
    (** fold and map at the same time *)

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    val fold_left: ('b -> key -> 'a -> 'b) -> 'b -> 'a t -> 'b
    (** same as {!fold} but in the order of {!List.fold_left} *)

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    val fold2_inter: (key -> 'a -> 'b -> 'c -> 'c) -> 'a t -> 'b t -> 'c -> 'c
    (** fold the common keys of two map at the same time *)

    val fold2_union:
      (key -> 'a option -> 'b option -> 'c -> 'c) -> 'a t -> 'b t -> 'c -> 'c
    (** fold the keys which appear in one of the two maps *)

    val translate : (key -> key) -> 'a t -> 'a t
    (** [translate f m] translates the keys in the map [m] by the
        function [f]. [f] must be strictly monotone on the key of [m].
        Otherwise it raises invalid_arg *)

    val mapi_filter_fold:
      (key -> 'a -> 'acc -> 'acc * 'b option) -> 'a t -> 'acc -> 'acc * 'b t
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    (** Same as {!Extmap.S.mapi_fold}, but may remove bindings. *)
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    val add_new : exn -> key -> 'a -> 'a t -> 'a t
    (** [add_new e x v m] binds [x] to [v] in [m] if [x] is not bound,
        and raises [e] otherwise. *)

    val keys: 'a t -> key list
    (** Return the list of all keys of the given map.
        The returned list is sorted in increasing order with respect
        to the ordering [Ord.compare], where [Ord] is the argument
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        given to {!Extmap.Make}. *)
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    val values: 'a t -> 'a list
    (** Return the list of all values of the given map.
        The returned list is sorted in increasing order with respect
        to the ordering [Ord.compare] of the keys, where [Ord] is the argument
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        given to {!Extmap.Make}. *)

    val of_list: (key * 'a) list -> 'a t
    (** construct a map from a pair of bindings *)
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    type 'a enumeration
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    (** enumeration: zipper style *)
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    val val_enum : 'a enumeration -> (key * 'a) option
    (** get the current key value pair of the enumeration, return None
        if the enumeration reach the end *)

    val start_enum : 'a t -> 'a enumeration
    (** start the enumeration of the given map *)

    val next_enum : 'a enumeration -> 'a enumeration
    (** get the next step of the enumeration *)

    val start_ge_enum : key -> 'a t -> 'a enumeration
    (** start the enumeration of the given map at the first key which
        is greater or equal than the given one *)

    val next_ge_enum : key -> 'a enumeration -> 'a enumeration
    (** get the next (or same) step of the enumeration which key is
        greater or equal to the given key *)
  end

  module Make (Ord : OrderedType) : S with type key = Ord.t
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  (** Functor building an implementation of the map structure
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      given a totally ordered type. *)