From 12c0c5a6f5ac7a0d9327654b58792a4bc4a54b6f Mon Sep 17 00:00:00 2001
From: Simon Cruanes <simon.cruanes.2007@m4x.org>
Date: Wed, 28 Aug 2013 15:01:09 +0200
Subject: [PATCH] fmap function

---
 sequence.ml  | 7 +++++++
 sequence.mli | 3 +++
 2 files changed, 10 insertions(+)

diff --git a/sequence.ml b/sequence.ml
index 549d1e2..cf7d1a5 100644
--- a/sequence.ml
+++ b/sequence.ml
@@ -129,6 +129,13 @@ let flatMap f seq =
   from_iter
     (fun k -> seq (fun x -> (f x) k))
 
+let fmap f seq =
+  from_iter
+    (fun k ->
+      seq (fun x -> match f x with
+          | None -> ()
+          | Some y -> k y))
+
 (** Insert the given element between every element of the sequence *)
 let intersperse elem seq =
   fun k ->
diff --git a/sequence.mli b/sequence.mli
index 16df438..c6602b0 100644
--- a/sequence.mli
+++ b/sequence.mli
@@ -125,6 +125,9 @@ val flatMap : ('a -> 'b t) -> 'a t -> 'b t
   (** Monadic bind. It applies the function to every element of the
       initial sequence, and calls [concat]. *)
 
+val fmap : ('a -> 'b option) -> 'a t -> 'b t
+  (** Specialized version of {!flatMap} for options.  *)
+
 val intersperse : 'a -> 'a t -> 'a t
   (** Insert the second element between every element of the sequence *)