ocaml-containers/src/core/CCMap.ml
2016-12-29 11:45:55 +01:00

126 lines
3.1 KiB
OCaml

(* This file is free software, part of containers. See file "license" for more details. *)
(** {1 Extensions of Standard Map} *)
type 'a sequence = ('a -> unit) -> unit
type 'a printer = Format.formatter -> 'a -> unit
module type S = sig
include Map.S
val get : key -> 'a t -> 'a option
(** Safe version of {!find} *)
val get_or : key -> 'a t -> default:'a -> 'a
(** [get_or k m ~default] returns the value associated to [k] if present,
and returns [default] otherwise (if [k] doesn't belong in [m])
@since 0.16 *)
val update : key -> ('a option -> 'a option) -> 'a t -> 'a t
(** [update k f m] calls [f (Some v)] if [find k m = v],
otherwise it calls [f None]. In any case, if the result is [None]
[k] is removed from [m], and if the result is [Some v'] then
[add k v' m] is returned. *)
val merge_safe :
f:(key -> [`Left of 'a | `Right of 'b | `Both of 'a * 'b] -> 'c option) ->
'a t -> 'b t -> 'c t
(** [merge_safe ~f a b] merges the maps [a] and [b] together.
@since 0.17 *)
val of_seq : (key * 'a) sequence -> 'a t
val add_seq : 'a t -> (key * 'a) sequence -> 'a t
(** @since 0.14 *)
val to_seq : 'a t -> (key * 'a) sequence
val of_list : (key * 'a) list -> 'a t
val add_list : 'a t -> (key * 'a) list -> 'a t
(** @since 0.14 *)
val keys : _ t -> key sequence
(** Iterate on keys only
@since 0.15 *)
val values : 'a t -> 'a sequence
(** Iterate on values only
@since 0.15 *)
val to_list : 'a t -> (key * 'a) list
val pp :
?start:string -> ?stop:string -> ?arrow:string -> ?sep:string ->
key printer -> 'a printer -> 'a t printer
end
module Make(O : Map.OrderedType) = struct
include Map.Make(O)
let get k m =
try Some (find k m)
with Not_found -> None
let get_or k m ~default =
try find k m
with Not_found -> default
let update k f m =
let x =
try f (Some (find k m))
with Not_found -> f None
in
match x with
| None -> remove k m
| Some v' -> add k v' m
let merge_safe ~f a b =
merge
(fun k v1 v2 -> match v1, v2 with
| None, None -> assert false
| Some v1, None -> f k (`Left v1)
| None, Some v2 -> f k (`Right v2)
| Some v1, Some v2 -> f k (`Both (v1,v2)))
a b
let add_seq m s =
let m = ref m in
s (fun (k,v) -> m := add k v !m);
!m
let of_seq s = add_seq empty s
let to_seq m yield =
iter (fun k v -> yield (k,v)) m
let keys m yield =
iter (fun k _ -> yield k) m
let values m yield =
iter (fun _ v -> yield v) m
let add_list m l = List.fold_left (fun m (k,v) -> add k v m) m l
let of_list l = add_list empty l
let to_list m =
fold (fun k v acc -> (k,v)::acc) m []
let pp ?(start="") ?(stop="") ?(arrow="->") ?(sep=", ") pp_k pp_v fmt m =
Format.pp_print_string fmt start;
let first = ref true in
iter
(fun k v ->
if !first then first := false
else (
Format.pp_print_string fmt sep;
Format.pp_print_cut fmt ()
);
pp_k fmt k;
Format.pp_print_string fmt arrow;
pp_v fmt v)
m;
Format.pp_print_string fmt stop
end