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(*
* ExtHashtbl - extra functions over hashtables.
* Copyright (C) 2003 Nicolas Cannasse
* 2009 David Teller, LIFO, Universite d'Orleans
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version,
* with the special exception on linking described in file LICENSE.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*)
(** Extra functions over hashtables. *)
(** Operations over hashtables.
This module replaces Stdlib's
{{:http://caml.inria.fr/pub/docs/manual-ocaml/libref/Hashtbl.html}Hashtbl}
module. All functions and types are provided here.
@author Xavier Leroy (base module)
@author Damien Doligez (base module)
@author Nicolas Cannasse
@author David Teller
*)
open Hashtbl
type ('a, 'b) t = ('a, 'b) Hashtbl.t
(** A Hashtable wth keys of type 'a and values 'b *)
(**{6 Base operations}*)
val create : int -> ('a, 'b) t
(** [Hashtbl.create n] creates a new, empty hash table, with
initial size [n]. For best results, [n] should be on the
order of the expected number of elements that will be in
the table. The table grows as needed, so [n] is just an
initial guess. *)
val length : ('a, 'b) t -> int
(** [Hashtbl.length tbl] returns the number of bindings in [tbl].
Multiple bindings are counted multiply, so [Hashtbl.length]
gives the number of times [Hashtbl.iter] calls its first argument. *)
val is_empty : ('a, 'b) t -> bool
(** [Hashtbl.is_empty tbl] returns [true] if there are no bindings
in [tbl], false otherwise.*)
val add : ('a, 'b) t -> 'a -> 'b -> unit
(** [Hashtbl.add tbl x y] adds a binding of [x] to [y] in table [tbl].
Previous bindings for [x] are not removed, but simply
hidden. That is, after performing {!Hashtbl.remove}[ tbl x],
the previous binding for [x], if any, is restored.
(Same behavior as with association lists.) *)
val remove : ('a, 'b) t -> 'a -> unit
(** [Hashtbl.remove tbl x] removes the current binding of [x] in [tbl],
restoring the previous binding if it exists.
It does nothing if [x] is not bound in [tbl]. *)
val remove_all : ('a,'b) t -> 'a -> unit
(** Remove all bindings for the given key *)
val replace : ('a, 'b) t -> 'a -> 'b -> unit
(** [Hashtbl.replace tbl x y] replaces the current binding of [x]
in [tbl] by a binding of [x] to [y]. If [x] is unbound in [tbl],
a binding of [x] to [y] is added to [tbl].
This is functionally equivalent to {!Hashtbl.remove}[ tbl x]
followed by {!Hashtbl.add}[ tbl x y]. *)
val copy : ('a, 'b) t -> ('a, 'b) t
(** Return a copy of the given hashtable. *)
val clear : ('a, 'b) t -> unit
(** Empty a hash table. *)
(**{6 Enumerations}*)
val keys : ('a,'b) t -> 'a BatEnum.t
(** Return an enumeration of all the keys of a hashtable.
If the key is in the Hashtable multiple times, all occurrences
will be returned. *)
val values : ('a,'b) t -> 'b BatEnum.t
(** Return an enumeration of all the values of a hashtable. *)
val enum : ('a, 'b) t -> ('a * 'b) BatEnum.t
(** Return an enumeration of (key,value) pairs of a hashtable. *)
val of_enum : ('a * 'b) BatEnum.t -> ('a, 'b) t
(** Create a hashtable from a (key,value) enumeration. *)
(**{6 Searching}*)
val find : ('a, 'b) t -> 'a -> 'b
(** [Hashtbl.find tbl x] returns the current binding of [x] in [tbl],
or raises [Not_found] if no such binding exists. *)
val find_all : ('a, 'b) t -> 'a -> 'b list
(** [Hashtbl.find_all tbl x] returns the list of all data
associated with [x] in [tbl].
The current binding is returned first, then the previous
bindings, in reverse order of introduction in the table. *)
val find_default : ('a,'b) t -> 'a -> 'b -> 'b
(** Find a binding for the key, and return a default
value if not found *)
val find_option : ('a,'b) Hashtbl.t -> 'a -> 'b option
(** Find a binding for the key, or return [None] if no
value is found *)
val mem : ('a, 'b) t -> 'a -> bool
(** [Hashtbl.mem tbl x] checks if [x] is bound in [tbl]. *)
(*val exists : ('a,'b) t -> 'a -> bool*)
(** [exists h k] returns true is at least one item with key [k] is
found in the hashtable. *)
(**{6 Traversing}
A number of higher-order functions are provided to allow
purely functional traversal or transformation of hashtables.
These functions are similar to their counterparts in module
{!BatEnum}.
Whenever you wish to traverse or transfor a hashtable, you have the
choice between using the more general functions of {!BatEnum}, with
{!keys}, {!values}, {!enum} and {!of_enum}, or the more optimized
functions of this section.
If you are new to OCaml or unsure about data structure, using the
functions of {!BatEnum} is a safe bet. Should you wish to improve
performance at the cost of generality, you will always be able to
rewrite your code to make use of the functions of this section.
*)
val iter : ('a -> 'b -> unit) -> ('a, 'b) t -> unit
(** [Hashtbl.iter f tbl] applies [f] to all bindings in table [tbl].
[f] receives the key as first argument, and the associated value
as second argument. Each binding is presented exactly once to [f].
The order in which the bindings are passed to [f] is unspecified.
However, if the table contains several bindings for the same key,
they are passed to [f] in reverse order of introduction, that is,
the most recent binding is passed first. *)
val fold : ('a -> 'b -> 'c -> 'c) -> ('a, 'b) t -> 'c -> 'c
(** [Hashtbl.fold f tbl init] computes
[(f kN dN ... (f k1 d1 (f k0 d0 init))...)],
where [k0,k1..kN] are the keys of all bindings in [tbl],
and [d0,d1..dN] are the associated values.
Each binding is presented exactly once to [f].
The order in which the bindings are passed to [f] is unspecified.
However, if the table contains several bindings for the same key,
they are passed to [f] in reverse order of introduction, that is,
the most recent binding is passed first. *)
val map : ('a -> 'b -> 'c) -> ('a,'b) t -> ('a,'c) t
(** [map f x] creates a new hashtable with the same
keys as [x], but with the function [f] applied to
all the values *)
val filter: ('a -> bool) -> ('key, 'a) t -> ('key, 'a) t
(**[filter f m] returns a new hashtable where only the values [a] of [m]
such that [f a = true] remain.*)
val filteri: ('key -> 'a -> bool) -> ('key, 'a) t -> ('key, 'a) t
(**[filter f m] returns a hashtbl where only the key, values pairs
[key], [a] of [m] such that [f key a = true] remain. The
bindings are passed to [f] in increasing order with respect
to the ordering over the type of the keys. *)
val filter_map: ('key -> 'a -> 'b option) -> ('key, 'a) t -> ('key, 'b) t
(** [filter_map f m] combines the features of [filteri] and [map]. It
calls [f key0 a0], [f key1 a1], [f keyn an] where [a0,a1..an] are
the elements of [m] and [key0..keyn] the corresponding keys. It
returns a hashtbl with associations [keyi],[bi] where [f keyi ai =
Some bi]. When [f] returns [None], the corresponding element of
[m] is discarded. *)
(** {6 The polymorphic hash primitive}*)
val hash : 'a -> int
(** [Hashtbl.hash x] associates a positive integer to any value of
any type. It is guaranteed that
if [x = y] or [Pervasives.compare x y = 0], then [hash x = hash y].
Moreover, [hash] always terminates, even on cyclic
structures. *)
external hash_param : int -> int -> 'a -> int = "caml_hash_univ_param" "noalloc"
(** [Hashtbl.hash_param n m x] computes a hash value for [x], with the
same properties as for [hash]. The two extra parameters [n] and
[m] give more precise control over hashing. Hashing performs a
depth-first, right-to-left traversal of the structure [x], stopping
after [n] meaningful nodes were encountered, or [m] nodes,
meaningful or not, were encountered. Meaningful nodes are: integers;
floating-point numbers; strings; characters; booleans; and constant
constructors. Larger values of [m] and [n] means that more
nodes are taken into account to compute the final hash
value, and therefore collisions are less likely to happen.
However, hashing takes longer. The parameters [m] and [n]
govern the tradeoff between accuracy and speed. *)
(** {6 Boilerplate code}*)
(** {7 Printing}*)
val print : ?first:string -> ?last:string -> ?sep:string -> ?kvsep:string ->
('a BatInnerIO.output -> 'b -> unit) ->
('a BatInnerIO.output -> 'c -> unit) ->
'a BatInnerIO.output -> ('b, 'c) t -> unit
(** {6 Override modules}*)
(**
The following modules replace functions defined in {!Hashtbl} with functions
behaving slightly differently but having the same name. This is by design:
the functions meant to override the corresponding functions of {!Hashtbl}.
*)
(** Operations on {!Hashtbl} without exceptions.
@documents Hashtbl.Exceptionless
*)
module Exceptionless :
sig
val find : ('a, 'b) t -> 'a -> 'b option
end
(** Infix operators over a {!BatHashtbl} *)
module Infix :
sig
val (-->) : ('a, 'b) t -> 'a -> 'b
(** [tbl-->x] returns the current binding of [x] in [tbl],
or raises [Not_found] if no such binding exists.
Equivalent to [Hashtbl.find tbl x]*)
val (<--) : ('a, 'b) t -> 'a * 'b -> unit
(** [tbl<--(x, y)] adds a binding of [x] to [y] in table [tbl].
Previous bindings for [x] are not removed, but simply
hidden. That is, after performing {!Hashtbl.remove}[ tbl x],
the previous binding for [x], if any, is restored.
(Same behavior as with association lists.)
Equivalent to [Hashtbl.add tbl x y]*)
end
(** Operations on {!Hashtbl} with labels.
This module overrides a number of functions of {!Hashtbl} by
functions in which some arguments require labels. These labels are
there to improve readability and safety and to let you change the
order of arguments to functions. In every case, the behavior of the
function is identical to that of the corresponding function of {!Hashtbl}.
@documents Hashtbl.Labels
*)
module Labels :
sig
val add : ('a, 'b) t -> key:'a -> data:'b -> unit
val replace : ('a, 'b) t -> key:'a -> data:'b -> unit
val iter : f:(key:'a -> data:'b -> unit) -> ('a, 'b) t -> unit
val map: f:(key:'a -> data:'b -> 'c) -> ('a, 'b) t -> ('a, 'c) t
val filter: f:('a -> bool) -> ('key, 'a) t -> ('key, 'a) t
val filteri:f:(key:'key -> data:'a -> bool) -> ('key, 'a) t -> ('key, 'a) t
val filter_map:f:(key:'key -> data:'a -> 'b option) -> ('key, 'a) t -> ('key, 'b) t
val fold :
f:(key:'a -> data:'b -> 'c -> 'c) ->
('a, 'b) t -> init:'c -> 'c
end
(** {6 Functorial interface} *)
module type HashedType =
sig
type t
(** The type of the hashtable keys. *)
val equal : t -> t -> bool
(** The equality predicate used to compare keys. *)
val hash : t -> int
(** A hashing function on keys. It must be such that if two keys are
equal according to [equal], then they have identical hash values
as computed by [hash].
Examples: suitable ([equal], [hash]) pairs for arbitrary key
types include
([(=)], {!Hashtbl.hash}) for comparing objects by structure,
([(fun x y -> compare x y = 0)], {!Hashtbl.hash})
for comparing objects by structure and handling {!Pervasives.nan}
correctly, and
([(==)], {!Hashtbl.hash}) for comparing objects by addresses
(e.g. for cyclic keys). *)
end
(** The output signature of the functor {!Hashtbl.Make}. *)
module type S =
sig
type key
type 'a t
val create : int -> 'a t
val length : 'a t -> int
val is_empty : 'a t -> bool
val clear : 'a t -> unit
val copy : 'a t -> 'a t
val add : 'a t -> key -> 'a -> unit
val remove : 'a t -> key -> unit
val remove_all : 'a t -> key -> unit
val find : 'a t -> key -> 'a
val find_all : 'a t -> key -> 'a list
val find_default : 'a t -> key -> 'a -> 'a
val find_option : 'a t -> key -> 'a option
val replace : 'a t -> key -> 'a -> unit
val mem : 'a t -> key -> bool
val iter : (key -> 'a -> unit) -> 'a t -> unit
val fold : (key -> 'a -> 'b -> 'b) -> 'a t -> 'b -> 'b
val map : (key -> 'b -> 'c) -> 'b t -> 'c t
val filter: ('a -> bool) -> 'a t -> 'a t
val filteri: (key -> 'a -> bool) -> 'a t -> 'a t
val filter_map: (key -> 'a -> 'b option) -> 'a t -> 'b t
val keys : 'a t -> key BatEnum.t
val values : 'a t -> 'a BatEnum.t
val enum : 'a t -> (key * 'a) BatEnum.t
val of_enum : (key * 'a) BatEnum.t -> 'a t
val print : ?first:string -> ?last:string -> ?sep:string ->
('a BatInnerIO.output -> key -> unit) ->
('a BatInnerIO.output -> 'b -> unit) ->
'a BatInnerIO.output -> 'b t -> unit
(** {6 Override modules}*)
(**
The following modules replace functions defined in {!Hashtbl} with functions
behaving slightly differently but having the same name. This is by design:
the functions meant to override the corresponding functions of {!Hashtbl}.
*)
(** Operations on {!Hashtbl} without exceptions.
@documents Hashtbl.S.Exceptionless*)
module Exceptionless :
sig
val find : 'a t -> key -> 'a option
end
(** Infix operators over a {!BatHashtbl} *)
module Infix :
sig
val (-->) : 'a t -> key -> 'a
(** [tbl-->x] returns the current binding of [x] in [tbl],
or raises [Not_found] if no such binding exists.
Equivalent to [Hashtbl.find tbl x]*)
val (<--) : 'a t -> key * 'a -> unit
(** [tbl<--(x, y)] adds a binding of [x] to [y] in table [tbl].
Previous bindings for [x] are not removed, but simply
hidden. That is, after performing {!Hashtbl.remove}[ tbl x],
the previous binding for [x], if any, is restored.
(Same behavior as with association lists.)
Equivalent to [Hashtbl.add tbl x y]*)
end
(** Operations on {!Hashtbl} with labels.
This module overrides a number of functions of {!Hashtbl} by
functions in which some arguments require labels. These labels are
there to improve readability and safety and to let you change the
order of arguments to functions. In every case, the behavior of the
function is identical to that of the corresponding function of {!Hashtbl}.
@documents Hashtbl.S.Labels
*)
module Labels :
sig
val add : 'a t -> key:key -> data:'a -> unit
val replace : 'a t -> key:key -> data:'a -> unit
val iter : f:(key:key -> data:'a -> unit) -> 'a t -> unit
val map : f:(key:key -> data:'a -> 'b) -> 'a t -> 'b t
val filter: f:('a -> bool) -> 'a t -> 'a t
val filteri: f:(key:key -> data:'a -> bool) -> 'a t -> 'a t
val filter_map: f:(key:key -> data:'a -> 'b option) -> 'a t -> 'b t
val fold : f:(key:key -> data:'a -> 'b -> 'b) -> 'a t -> init:'b -> 'b
end
end
(** The output signature of the functor {!Hashtbl.Make}. *)
module Make (H : HashedType) : S with type key = H.t
(** Functor building an implementation of the hashtable structure.
The functor [Hashtbl.Make] returns a structure containing
a type [key] of keys and a type ['a t] of hash tables
associating data of type ['a] to keys of type [key].
The operations perform similarly to those of the generic
interface, but use the hashing and equality functions
specified in the functor argument [H] instead of generic
equality and hashing. *)
(** Capabilities for hashtables.
@documents Hashtbl.Cap
*)
module Cap :
sig
type ('a, 'b, 'c) t constraint 'c = [< `Read | `Write ]
(** The type of a hashtable. *)
(**{6 Constructors}*)
val create : int -> ('a, 'b, _) t
external of_table : ('a, 'b) Hashtbl.t -> ('a, 'b, _ ) t = "%identity"
(** Adopt a regular hashtable as a capability hashtble, allowing
to decrease capabilities if necessary.
This operation involves no copying. In other words, in
[let cap = of_table a in ...], any modification in [a]
will also have effect on [cap] and reciprocally.*)
external to_table : ('a, 'b, [`Read | `Write]) t -> ('a, 'b) Hashtbl.t = "%identity"
(** Return a capability hashtable as a regular hashtable.
This operation requires both read and write permissions
on the capability table and involves no copying. In other
words, in [let a = of_table cap in ...], any modification
in [a] will also have effect on [cap] and reciprocally.*)
external read_only : ('a, 'b, [>`Read]) t -> ('a, 'b, [`Read]) t = "%identity"
(** Drop to read-only permissions.
This operation involves no copying.*)
external write_only : ('a, 'b, [>`Write]) t -> ('a, 'b, [`Write]) t = "%identity"
(** Drop to write-only permissions.
This operation involves no copying.*)
(**{6 Base operations}*)
val length : ('a, 'b, _) t -> int
val is_empty : ('a, 'b, _) t -> bool
val add : ('a, 'b, [>`Write]) t -> 'a -> 'b -> unit
val remove : ('a, 'b, [>`Write]) t -> 'a -> unit
val remove_all : ('a,'b, [>`Write]) t -> 'a -> unit
val replace : ('a, 'b, [>`Write]) t -> 'a -> 'b -> unit
val copy : ('a, 'b, [>`Read]) t -> ('a, 'b, _) t
val clear : ('a, 'b, [>`Write]) t -> unit
(**{6 Searching}*)
val find : ('a, 'b, [>`Read]) t -> 'a -> 'b
val find_all : ('a, 'b, [>`Read]) t -> 'a -> 'b list
val find_default : ('a, 'b, [>`Read]) t -> 'a -> 'b -> 'b
val find_option : ('a, 'b, [>`Read]) t -> 'a -> 'b option
val mem : ('a, 'b, [>`Read]) t -> 'a -> bool
(*val exists : ('a,'b) t -> 'a -> bool*)
(** [exists h k] returns true is at least one item with key [k] is
found in the hashtable. *)
(**{6 Traversing}*)
val iter : ('a -> 'b -> unit) -> ('a, 'b, [>`Read]) t -> unit
val fold : ('a -> 'b -> 'c -> 'c) -> ('a, 'b, [>`Read]) t -> 'c -> 'c
val map : ('a -> 'b -> 'c) -> ('a, 'b, [>`Read]) t -> ('a, 'c, _) t
val filter: ('a -> bool) -> ('key, 'a, [>`Read]) t -> ('key, 'a, _) t
val filteri: ('key -> 'a -> bool) -> ('key, 'a, [>`Read]) t -> ('key, 'a, _) t
val filter_map: ('key -> 'a -> 'b option) -> ('key, 'a, [>`Read]) t -> ('key, 'b, _) t
(**{6 Conversions}*)
val keys : ('a,'b, [>`Read]) t -> 'a BatEnum.t
val values : ('a, 'b, [>`Read]) t -> 'b BatEnum.t
val enum : ('a, 'b, [>`Read]) t -> ('a * 'b) BatEnum.t
val of_enum : ('a * 'b) BatEnum.t -> ('a, 'b, _) t
(** {6 Boilerplate code}*)
(** {7 Printing}*)
val print : ?first:string -> ?last:string -> ?sep:string -> ?kvsep:string ->
('a BatInnerIO.output -> 'b -> unit) ->
('a BatInnerIO.output -> 'c -> unit) ->
'a BatInnerIO.output -> ('b, 'c, [>`Read]) t -> unit
(** {6 Override modules}*)
(** Operations on {!BatHashtbl.Cap} without exceptions.*)
module Exceptionless :
sig
val find : ('a, 'b, [>`Read]) t -> 'a -> 'b option
end
(** Operations on {!BatHashtbl.Cap} with labels.*)
module Labels :
sig
val add : ('a, 'b, [>`Write]) t -> key:'a -> data:'b -> unit
val replace : ('a, 'b, [>`Write]) t -> key:'a -> data:'b -> unit
val iter : f:(key:'a -> data:'b -> unit) -> ('a, 'b, [>`Read]) t -> unit
val map : f:(key:'a -> data:'b -> 'c) -> ('a, 'b, [>`Read]) t -> ('a, 'c, _) t
val filter: f:('a -> bool) -> ('key, 'a, [>`Read]) t -> ('key, 'a, _) t
val filteri: f:(key:'key -> data:'a -> bool) -> ('key, 'a, [>`Read]) t -> ('key, 'a, _) t
val filter_map: f:(key:'key -> data:'a -> 'b option) -> ('key, 'a, [>`Read]) t -> ('key, 'b, _) t
val fold : f:(key:'a -> data:'b -> 'c -> 'c) ->
('a, 'b, [>`Read]) t -> init:'c -> 'c
end
end
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