diff --git a/src/Data/OrderedMap.hs b/src/Data/OrderedMap.hs
index 09f37ae..d534332 100644
--- a/src/Data/OrderedMap.hs
+++ b/src/Data/OrderedMap.hs
@@ -7,11 +7,13 @@ module Data.OrderedMap (
     , get
     , keys
     , lookup
+    , mapi
+    , set
     , toList
   ) where
 
-import Data.Map (Map, (!))
-import qualified Data.Map as Map (fromList, lookup)
+import Data.Map (Map, (!), mapWithKey)
+import qualified Data.Map as Map (fromList, insert, lookup, member)
 import Prelude hiding (lookup)
 
 data OrderedMap k a = OrderedMap {
@@ -56,6 +58,16 @@ get k = (! k) . assoc
 lookup :: Ord k => k -> OrderedMap k a -> Maybe a
 lookup k = (Map.lookup k) . assoc
 
+set :: Ord k => k -> a -> OrderedMap k a -> OrderedMap k a
+set k v orderedMap@(OrderedMap {assoc})
+  | Map.member k assoc = orderedMap {assoc = Map.insert k v assoc}
+  | otherwise = orderedMap
+
+mapi :: Ord k => (k -> a -> b) -> OrderedMap k a -> OrderedMap k b
+mapi f orderedMap = orderedMap {
+    assoc = mapWithKey f $ assoc orderedMap
+  }
+
 {-
 cons :: Ord k => k -> a -> OrderedMap k a -> OrderedMap k a
 cons k a orderedMap =