From b8b93651af0745be5aad4261ba47ebb7f66a831d Mon Sep 17 00:00:00 2001
From: Eitan Chatav <eitan.chatav@gmail.com>
Date: Fri, 4 Nov 2016 12:22:22 -0700
Subject: [PATCH] composition operator

added composition operator to utils module
---
 src/node/net/p2p.ml | 4 ++--
 src/utils/utils.ml  | 2 ++
 src/utils/utils.mli | 2 ++
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/node/net/p2p.ml b/src/node/net/p2p.ml
index f19af5cfc..9bf11f423 100644
--- a/src/node/net/p2p.ml
+++ b/src/node/net/p2p.ml
@@ -434,8 +434,8 @@ let addr_encoding =
 let public_key_encoding =
   let open Data_encoding in
     conv
-      (fun public_key -> MBytes.to_string (Crypto_box.of_public_key public_key))
-      (fun str -> Crypto_box.to_public_key (MBytes.of_string str))
+      (MBytes.to_string << Crypto_box.of_public_key)
+      (Crypto_box.to_public_key << MBytes.of_string)
       string
 
 let peers_file_encoding =
diff --git a/src/utils/utils.ml b/src/utils/utils.ml
index ef2fe1f48..97969003d 100644
--- a/src/utils/utils.ml
+++ b/src/utils/utils.ml
@@ -121,3 +121,5 @@ let rec remove_elem_from_list nb = function
   | [] -> []
   | l when nb <= 0 -> l
   | _ :: tl -> remove_elem_from_list (nb - 1) tl
+
+let (<<) g f = fun a -> g (f a)
diff --git a/src/utils/utils.mli b/src/utils/utils.mli
index a027b783f..f2abbdf92 100644
--- a/src/utils/utils.mli
+++ b/src/utils/utils.mli
@@ -38,3 +38,5 @@ val remove_elem_from_list: int -> 'a list -> 'a list
 
 val filter_map: ('a -> 'b option) -> 'a list -> 'b list
 
+(** Compose functions from right to left. *)
+val (<<) : ('b -> 'c) -> ('a -> 'b) -> 'a -> 'c