a bunch of useful functions in CCMap

core/CCMap.ml

@@ -26,16 +26,95 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 (** {1 Extensions of Standard Map} *)
 
+type 'a sequence = ('a -> unit) -> unit
+type 'a printer = Buffer.t -> 'a -> unit
+type 'a formatter = Format.formatter -> 'a -> unit
+
 module type S = sig
   include Map.S
 
+  val get : key -> 'a t -> 'a option
+  (** Safe version of {!find} *)
+
+  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 of_seq : (key * 'a) sequence -> 'a t
+
+  val to_seq : 'a t -> (key * 'a) sequence
+
+  val of_list : (key * 'a) list -> 'a t
+
   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
+
+  val print : ?start:string -> ?stop:string -> ?arrow:string -> ?sep:string ->
+              key formatter -> 'a formatter -> 'a t formatter
 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 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 of_seq s =
+    let m = ref empty in
+    s (fun (k,v) -> m := add k v !m);
+    !m
+
+  let to_seq m yield =
+    iter (fun k v -> yield (k,v)) m
+
+  let of_list l =
+    List.fold_left
+      (fun m (k,v) -> add k v m) 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 buf m =
+    let first = ref true in
+    Buffer.add_string buf start;
+    iter
+      (fun k v ->
+        if !first then first := false else Buffer.add_string buf sep;
+        pp_k buf k;
+        Buffer.add_string buf arrow;
+        pp_v buf v
+      ) m;
+    Buffer.add_string buf stop
+
+  (*$T
+    CCPrint.to_string (pp CCPrint.int) [1;2;3] = "[1, 2, 3]"
+    *)
+
+  let print ?(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;
+        pp_k fmt k;
+        Format.pp_print_string fmt arrow;
+        pp_v fmt v;
+        Format.pp_print_cut fmt ()
+      ) m;
+    Format.pp_print_string fmt stop
 end
 

core/CCMap.mli

@@ -29,10 +29,35 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 Provide useful functions and iterators on [Map.S]
 @since NEXT_RELEASE *)
 
+type 'a sequence = ('a -> unit) -> unit
+type 'a printer = Buffer.t -> 'a -> unit
+type 'a formatter = Format.formatter -> 'a -> unit
+
 module type S = sig
   include Map.S
 
+  val get : key -> 'a t -> 'a option
+  (** Safe version of {!find} *)
+
+  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 of_seq : (key * 'a) sequence -> 'a t
+
+  val to_seq : 'a t -> (key * 'a) sequence
+
+  val of_list : (key * 'a) list -> 'a t
+
   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
+
+  val print : ?start:string -> ?stop:string -> ?arrow:string -> ?sep:string ->
+              key formatter -> 'a formatter -> 'a t formatter
 end
 
 module Make(O : Map.OrderedType) : S