1 (***********************************************************************)
5 (* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
7 (* Copyright 1996 Institut National de Recherche en Informatique et *)
8 (* en Automatique. All rights reserved. This file is distributed *)
9 (* under the terms of the GNU Library General Public License, with *)
10 (* the special exception on linking described in file ../LICENSE. *)
12 (***********************************************************************)
14 (* $Id: myMap.mli,v 1.3 2006/02/17 16:19:52 pottier Exp $ *)
16 (** Association tables over ordered types.
18 This module implements applicative association tables, also known as
19 finite maps or dictionaries, given a total ordering function
21 All operations over maps are purely applicative (no side-effects).
22 The implementation uses balanced binary trees, and therefore searching
23 and insertion take time logarithmic in the size of the map.
26 module type OrderedType =
29 (** The type of the map keys. *)
30 val compare : t -> t -> int
31 (** A total ordering function over the keys.
32 This is a two-argument function [f] such that
33 [f e1 e2] is zero if the keys [e1] and [e2] are equal,
34 [f e1 e2] is strictly negative if [e1] is smaller than [e2],
35 and [f e1 e2] is strictly positive if [e1] is greater than [e2].
36 Example: a suitable ordering function is the generic structural
37 comparison function {!Pervasives.compare}. *)
39 (** Input signature of the functor {!Map.Make}. *)
44 (** The type of the map keys. *)
47 (** The type of maps from type [key] to type ['a]. *)
52 val is_empty: 'a t -> bool
53 (** Test whether a map is empty or not. *)
55 val add: key -> 'a -> 'a t -> 'a t
56 (** [add x y m] returns a map containing the same bindings as
57 [m], plus a binding of [x] to [y]. If [x] was already bound
58 in [m], its previous binding disappears. *)
60 val find: key -> 'a t -> 'a
61 (** [find x m] returns the current binding of [x] in [m],
62 or raises [Not_found] if no such binding exists. *)
64 val remove: key -> 'a t -> 'a t
65 (** [remove x m] returns a map containing the same bindings as
66 [m], except for [x] which is unbound in the returned map. *)
68 val mem: key -> 'a t -> bool
69 (** [mem x m] returns [true] if [m] contains a binding for [x],
70 and [false] otherwise. *)
72 val iter: (key -> 'a -> unit) -> 'a t -> unit
73 (** [iter f m] applies [f] to all bindings in map [m].
74 [f] receives the key as first argument, and the associated value
75 as second argument. The bindings are passed to [f] in increasing
76 order with respect to the ordering over the type of the keys.
77 Only current bindings are presented to [f]:
78 bindings hidden by more recent bindings are not passed to [f]. *)
80 val map: ('a -> 'b) -> 'a t -> 'b t
81 (** [map f m] returns a map with same domain as [m], where the
82 associated value [a] of all bindings of [m] has been
83 replaced by the result of the application of [f] to [a].
84 The bindings are passed to [f] in increasing order
85 with respect to the ordering over the type of the keys. *)
87 val mapi: (key -> 'a -> 'b) -> 'a t -> 'b t
88 (** Same as {!Map.S.map}, but the function receives as arguments both the
89 key and the associated value for each binding of the map. *)
91 val fold: (key -> 'a -> 'b -> 'b) -> 'a t -> 'b -> 'b
92 (** [fold f m a] computes [(f kN dN ... (f k1 d1 a)...)],
93 where [k1 ... kN] are the keys of all bindings in [m]
94 (in increasing order), and [d1 ... dN] are the associated data. *)
96 val compare: ('a -> 'a -> int) -> 'a t -> 'a t -> int
97 (** Total ordering between maps. The first argument is a total ordering
98 used to compare data associated with equal keys in the two maps. *)
100 val equal: ('a -> 'a -> bool) -> 'a t -> 'a t -> bool
101 (** [equal cmp m1 m2] tests whether the maps [m1] and [m2] are
102 equal, that is, contain equal keys and associate them with
103 equal data. [cmp] is the equality predicate used to compare
104 the data associated with the keys. *)
107 key option * key option
108 (** A type of key intervals. An interval consists of a lower bound
109 and an upper bound, each of which can be absent. A key is
110 considered to lie within the interval if it is both greater than
111 (or equal to) the lower bound (if present) and less than (or
112 equal to) the upper bound (if present). *)
114 val split: interval -> 'a t -> 'a t
115 (* [split interval m] is a map that consists of all bindings in [m]
116 whose keys lie within [interval]. *)
118 val minimum: 'a t -> key * 'a
119 (* [minimum m] returns the binding that corresponds to the minimum
120 (smallest) key within the map [m]. If [m] is empty, [Not_found]
123 val find_remove: key -> 'a t -> 'a * 'a t
124 (** [find_remove x m] returns a pair of the current binding of [x]
125 in [m], and a map containing the same bindings as [m], except
126 for [x] which is unbound in the returned map. [Not_found] is
127 raised if no binding for [x] exists. *)
129 val update: key -> ('a -> 'a) -> 'a t -> 'a t
130 (** If [m] maps [x] to [d], then [update x f m] maps [x] to [f d]
131 and coincides with [m] elsewhere. A binding for [x] in [m]
134 val restrict: (key -> bool) -> 'a t -> 'a t
135 (** [restrict p m] is the restriction of the map [m] to only
136 the keys that satisfy predicate [p]. *)
139 (** Output signature of the functor {!Map.Make}. *)
141 module Make (Ord : OrderedType) : S with type key = Ord.t
142 (** Functor building an implementation of the map structure
143 given a totally ordered type. *)