From 0cf5e4d5195b717590ac938df796c69399a4ca07 Mon Sep 17 00:00:00 2001
From: Igor Savchuk <i.savchuk@timeweb.ru>
Date: Mon, 7 Jul 2014 13:43:35 +0400
Subject: add maps:only/2

---
 lib/stdlib/src/maps.erl | 11 +++++++++++
 1 file changed, 11 insertions(+)

(limited to 'lib/stdlib')

diff --git a/lib/stdlib/src/maps.erl b/lib/stdlib/src/maps.erl
index 4ef1638e6d..b8b284db65 100644
--- a/lib/stdlib/src/maps.erl
+++ b/lib/stdlib/src/maps.erl
@@ -24,6 +24,7 @@
 	map/2,
 	size/1,
     without/2,
+    only/2,
     get/3
     ]).
 
@@ -201,3 +202,13 @@ size(Map) when is_map(Map) ->
 
 without(Ks, M) when is_list(Ks), is_map(M) ->
     maps:from_list([{K,V}||{K,V} <- maps:to_list(M), not lists:member(K, Ks)]).
+
+
+-spec only(Ks, Map1) -> Map2 when
+    Ks :: [K],
+    Map1 :: map(),
+    Map2 :: map(),
+    K :: term().
+
+only(Ks, M) when is_list(Ks), is_map(M) ->
+    maps:from_list([{K,V}||{K,V} <- maps:to_list(M), lists:member(K, Ks)]).
-- 
cgit v1.2.3