From ec922f682120f745e445e8dc2449f2e3459d582e Mon Sep 17 00:00:00 2001
From: Vincent Bernardoff <vb@luminar.eu.org>
Date: Tue, 29 Nov 2016 14:51:36 +0100
Subject: [PATCH] Utils: add first_some

---
 src/utils/utils.ml  | 5 +++++
 src/utils/utils.mli | 1 +
 2 files changed, 6 insertions(+)

diff --git a/src/utils/utils.ml b/src/utils/utils.ml
index 1f1a45717..b52aab3c9 100644
--- a/src/utils/utils.ml
+++ b/src/utils/utils.ml
@@ -112,6 +112,11 @@ let unopt_list l =
   let may_cons xs x = match x with None -> xs | Some x -> x :: xs in
   List.rev @@ List.fold_left may_cons [] l
 
+let first_some a b = match a, b with
+  | None, None -> None
+  | None, Some v -> Some v
+  | Some v, _ -> Some v
+
 let filter_map f l =
   let may_cons xs x = match f x with None -> xs | Some x -> x :: xs in
   List.rev @@ List.fold_left may_cons [] l
diff --git a/src/utils/utils.mli b/src/utils/utils.mli
index 4ca6ea823..e42aaa302 100644
--- a/src/utils/utils.mli
+++ b/src/utils/utils.mli
@@ -31,6 +31,7 @@ val apply_option: f:('a -> 'b option) -> 'a option -> 'b option
 val iter_option: f:('a -> unit) -> 'a option -> unit
 val unopt: 'a -> 'a option -> 'a
 val unopt_list: 'a option list -> 'a list
+val first_some: 'a option -> 'a option -> 'a option
 
 val display_paragraph: Format.formatter -> string -> unit