From e704020e3507fc5f781bc2db422a793355c72ff8 Mon Sep 17 00:00:00 2001
From: Simon Cruanes <simon.cruanes.2007@m4x.org>
Date: Wed, 20 Jul 2016 17:48:15 +0200
Subject: [PATCH] additional functions in CCMultiSet

---
 src/data/CCMultiSet.ml  | 51 ++++++++++++++++++++++++++++++++++++++++-
 src/data/CCMultiSet.mli | 12 ++++++++++
 2 files changed, 62 insertions(+), 1 deletion(-)

diff --git a/src/data/CCMultiSet.ml b/src/data/CCMultiSet.ml
index b9356cf7..c5c0bd3c 100644
--- a/src/data/CCMultiSet.ml
+++ b/src/data/CCMultiSet.ml
@@ -24,31 +24,53 @@ module type S = sig
   val remove : t -> elt -> t
 
   val add_mult : t -> elt -> int -> t
+  (** [add_mult set x n] adds [n] occurrences of [x] to [set]
+      @raise Invalid_argument if [n < 0]
+      @since 0.6 *)
 
   val remove_mult : t -> elt -> int -> t
+  (** [remove_mult set x n] removes at most [n] occurrences of [x] from [set]
+      @raise Invalid_argument if [n < 0]
+      @since 0.6 *)
 
   val update : t -> elt -> (int -> int) -> t
+  (** [update set x f] calls [f n] where [n] is the current multiplicity
+      of [x] in [set] ([0] to indicate its absence); the result of [f n]
+      is the new multiplicity of [x].
+      @raise Invalid_argument if [f n < 0]
+      @since 0.6 *)
 
   val min : t -> elt
+  (** Minimal element w.r.t the total ordering on elements *)
 
   val max : t -> elt
+  (** Maximal element w.r.t the total ordering on elements *)
 
   val union : t -> t -> t
+  (** [union a b] contains as many occurrences of an element [x]
+      as [count a x + count b x]. *)
 
   val meet : t -> t -> t
+  (** [meet a b] is a multiset such that
+      [count (meet a b) x = max (count a x) (count b x)] *)
 
   val intersection : t -> t -> t
+  (** [intersection a b] is a multiset such that
+      [count (intersection a b) x = min (count a x) (count b x)] *)
 
   val diff : t -> t -> t
+  (** MultiSet difference.
+      [count (diff a b) x = max (count a x - count b x) 0] *)
 
   val contains : t -> t -> bool
+  (** [contains a x = (count m x > 0)] *)
 
   val compare : t -> t -> int
 
   val equal : t -> t -> bool
 
   val cardinal : t -> int
-    (** Number of distinct elements *)
+  (** Number of distinct elements *)
 
   val iter : t -> (int -> elt -> unit) -> unit
 
@@ -61,6 +83,18 @@ module type S = sig
   val to_seq : t -> elt sequence
 
   val of_seq : elt sequence -> t
+
+  val of_list_mult : (elt * int) list -> t
+  (** @since NEXT_RELEASE *)
+
+  val to_list_mult : t -> (elt * int) list
+  (** @since NEXT_RELEASE *)
+
+  val to_seq_mult : t -> (elt * int) sequence
+  (** @since NEXT_RELEASE *)
+
+  val of_seq_mult : (elt * int) sequence -> t
+  (** @since NEXT_RELEASE *)
 end
 
 module Make(O : Set.OrderedType) = struct
@@ -199,6 +233,21 @@ module Make(O : Set.OrderedType) = struct
     let m = ref empty in
     seq (fun x -> m := add !m x);
     !m
+
+  let of_list_mult l =
+    List.fold_left
+      (fun s (x,i) -> add_mult s x i)
+      empty l
+
+  let to_list_mult m =
+    fold m [] (fun acc n x -> (x,n) :: acc)
+
+  let to_seq_mult m k = M.iter (fun x n -> k (x,n)) m
+
+  let of_seq_mult seq =
+    let m = ref empty in
+    seq (fun (x,n) -> m := add_mult !m x n);
+    !m
 end
 
 (*$T
diff --git a/src/data/CCMultiSet.mli b/src/data/CCMultiSet.mli
index ef7174ce..4b83ee70 100644
--- a/src/data/CCMultiSet.mli
+++ b/src/data/CCMultiSet.mli
@@ -83,6 +83,18 @@ module type S = sig
   val to_seq : t -> elt sequence
 
   val of_seq : elt sequence -> t
+
+  val of_list_mult : (elt * int) list -> t
+  (** @since NEXT_RELEASE *)
+
+  val to_list_mult : t -> (elt * int) list
+  (** @since NEXT_RELEASE *)
+
+  val to_seq_mult : t -> (elt * int) sequence
+  (** @since NEXT_RELEASE *)
+
+  val of_seq_mult : (elt * int) sequence -> t
+  (** @since NEXT_RELEASE *)
 end
 
 module Make(O : Set.OrderedType) : S with type elt = O.t