From bd00733ef04e4c916ab4a00d80e9ee1142bcd410 Mon Sep 17 00:00:00 2001
From: Maxime Dénès
Date: Tue, 25 Aug 2020 23:29:05 +0200
Subject: Wrap future goals into a module

---
 clib/option.ml  | 2 ++
 clib/option.mli | 3 +++
 2 files changed, 5 insertions(+)

(limited to 'clib')

diff --git a/clib/option.ml b/clib/option.ml
index c335e836c2..d1775ae3ae 100644
--- a/clib/option.ml
+++ b/clib/option.ml
@@ -55,6 +55,8 @@ let make x = Some x
 (** [bind x f] is [f y] if [x] is [Some y] and [None] otherwise *)
 let bind x f = match x with Some y -> f y | None -> None
 
+let filter f x = bind x (fun v -> if f v then x else None)
+
 (** [init b x] returns [Some x] if [b] is [true] and [None] otherwise. *)
 let init b x =
   if b then
diff --git a/clib/option.mli b/clib/option.mli
index 4c5df30179..4672780cab 100644
--- a/clib/option.mli
+++ b/clib/option.mli
@@ -46,6 +46,9 @@ val make : 'a -> 'a option
 (** [bind x f] is [f y] if [x] is [Some y] and [None] otherwise *)
 val bind : 'a option -> ('a -> 'b option) -> 'b option
 
+(** [filter f x] is [x] if [x] [Some y] and [f y] is true, [None] otherwise *)
+val filter : ('a -> bool) -> 'a option -> 'a option
+
 (** [init b x] returns [Some x] if [b] is [true] and [None] otherwise. *)
 val init : bool -> 'a -> 'a option
 
-- 
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