diff --git a/salak-yaml.cabal b/salak-yaml.cabal
--- a/salak-yaml.cabal
+++ b/salak-yaml.cabal
@@ -1,6 +1,6 @@
 cabal-version: 1.12
 name: salak-yaml
-version: 0.2.10
+version: 0.3
 license: BSD3
 license-file: LICENSE
 copyright: (c) 2018 Daniel YU
@@ -26,7 +26,7 @@
         base >=4.10 && <5,
         conduit >=1.3.1.1 && <1.4,
         libyaml >=0.1.1.0 && <0.2,
-        salak >=0.2.10 && <0.3,
+        salak ==0.3.*,
         text >=1.2.3.1 && <1.3
 
 test-suite spec
@@ -42,8 +42,9 @@
         QuickCheck >=2.13.2 && <2.14,
         base >=4.10 && <5,
         conduit >=1.3.1.1 && <1.4,
+        exceptions >=0.10.2 && <0.11,
         hspec ==2.*,
         libyaml >=0.1.1.0 && <0.2,
         mtl >=2.2.2 && <2.3,
-        salak >=0.2.10 && <0.3,
+        salak ==0.3.*,
         text >=1.2.3.1 && <1.3
diff --git a/src/Salak/Yaml.hs b/src/Salak/Yaml.hs
--- a/src/Salak/Yaml.hs
+++ b/src/Salak/Yaml.hs
@@ -14,6 +14,7 @@
 module Salak.Yaml(
     YAML(..)
   , loadYaml
+  , runSalakWithYaml
   ) where
 
 import           Control.Exception      (throwIO)
@@ -21,12 +22,16 @@
 import           Data.Conduit           hiding (Source)
 import           Data.Text.Encoding     (decodeUtf8)
 import           Salak
-import           Salak.Load
+import           Salak.Internal
+import qualified Salak.Trie             as T
 import           Text.Libyaml
 
+runSalakWithYaml :: (MonadCatch m, MonadIO m) => FilePath -> RunSalakT m a -> m a
+runSalakWithYaml name = runSalakWith name YAML
+
 -- | Load Yaml
-loadYaml :: MonadIO m => FilePath -> LoadSalakT m ()
-loadYaml file = load file $ \i s -> liftIO $ runConduitRes (decodeFileMarked file .| loadYAML i s)
+loadYaml :: FilePath -> LoadSalak ()
+loadYaml file = loadTrie True file (\i -> runConduitRes (decodeFileMarked file .| loadYAML i T.empty))
 
 -- | YAML notation for `loadYaml`
 data YAML = YAML
@@ -34,32 +39,34 @@
 instance HasLoad YAML where
   loaders _ = (, loadYaml) <$> ["yaml", "yml"]
 
-loadYAML :: MonadIO m => Priority -> Source -> ConduitM MarkedEvent o m Source
-loadYAML i s = await >>= maybe (return s) go
+loadYAML :: MonadIO m => Int -> TraceSource -> ConduitM MarkedEvent o m TraceSource
+loadYAML i = start
   where
-    go (MarkedEvent (EventScalar a _ _ _) _ _) = return (insertSource (newVStr (decodeUtf8 a) i) s)
-    go (MarkedEvent EventSequenceStart{}  _ _) = goSeq 0 s
-    go (MarkedEvent EventSequenceEnd      _ _) = return emptySource
-    go (MarkedEvent EventMappingStart{}  _ ee) = goMap ee s
-    go (MarkedEvent (EventAlias a)       _ ee) = ge ee $ "alias " ++ a ++ " not supported by salak"
-    go _ = loadYAML i s
-    goSeq j s1 = do
-      s' <- loadYAML i emptySource
-      if nullSource s'
-        then return s1
-        else updateSource (SNum j) (\_ -> return s') s1 >>= goSeq (j+1)
-    goMap ee s1 = do
+    start ts = await >>= maybe (return ts) (go ts)
+
+    go _  (MarkedEvent (EventAlias a) _ ee)       = ge ee $ "alias " ++ a ++ " not supported by salak"
+    go ts (MarkedEvent (EventScalar a _ _ _) _ _) = return $ setVal i a ts
+    go ts (MarkedEvent EventSequenceStart{}  _ _) = goS 0 ts
+    go ts (MarkedEvent EventMappingStart{}   _ _) = goM ts
+    go ts  _                                      = start ts
+
+    goS j ts = do
       v <- await
       case v of
-        Nothing -> ge ee "suppose to have data"
-        Just (MarkedEvent (EventScalar a _ _ _) _ ee') ->
-          updateSources (simpleSelectors $ decodeUtf8 a) (loadYAML i) s1 >>= goMap ee'
-        Just (MarkedEvent EventMappingEnd _ _) -> return s1
+        Nothing -> liftIO $ throwIO $ YamlException "unexpected end"
+        Just (MarkedEvent EventSequenceEnd _ _) -> return ts
+        Just e -> do
+          val <- go T.empty e
+          goS (j+1) (T.modify (KI j) (const val) ts)
+
+    goM ts = do
+      v <- await
+      case v of
+        Nothing -> liftIO $ throwIO $ YamlException "unexpected end"
+        Just (MarkedEvent EventMappingEnd _ _) -> return ts
+        Just (MarkedEvent (EventScalar a _ _ _) _ _) -> do
+                val <- start T.empty
+                goM $ T.modify' (Keys $ simpleKeys $ decodeUtf8 a) (const val) ts
         Just e -> ge (yamlStartMark e) ("suppose scalar and mapping end, but is " ++ show (yamlEvent e))
     ge YamlMark{..} e = liftIO $ throwIO $ YamlException $ "(" ++ show yamlLine ++ "," ++ show yamlColumn ++ ")" ++ e
-
-
-
-
-
 
diff --git a/test/Spec.hs b/test/Spec.hs
--- a/test/Spec.hs
+++ b/test/Spec.hs
@@ -1,16 +1,22 @@
-{-# LANGUAGE DataKinds           #-}
-{-# LANGUAGE DeriveGeneric       #-}
-{-# LANGUAGE FlexibleContexts    #-}
-{-# LANGUAGE OverloadedStrings   #-}
-{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE DataKinds             #-}
+{-# LANGUAGE DeriveGeneric         #-}
+{-# LANGUAGE FlexibleContexts      #-}
+{-# LANGUAGE FlexibleInstances     #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE OverloadedStrings     #-}
+{-# LANGUAGE RecordWildCards       #-}
+{-# LANGUAGE ScopedTypeVariables   #-}
 
 module Main where
 
+import           Control.Monad.Catch
 import           Control.Monad.Reader
 import           Data.List            (intercalate)
 import           Data.Text            (Text, pack)
+import           Debug.Trace
 import           GHC.Generics
 import           Salak
+import           Salak.Internal
 import           Salak.Yaml
 import           Test.Hspec
 import           Test.QuickCheck
@@ -46,17 +52,18 @@
 data SubConf = SubConf
   { hello :: String } deriving (Eq, Show, Generic)
 
-instance FromProp SubConf where
+instance MonadCatch m => FromProp m SubConf where
   fromProp = SubConf <$> "hello" .?= "yyy"
 
-instance FromProp Conf
+instance MonadCatch m => FromProp m Conf
 
 jsonProperty :: SpecWith ()
 jsonProperty = do
   context "load json" $ do
     it "salak.yml" $ do
       loadAndRunSalak (loadYaml "test/salak.yml") $ do
-        as <- require "array"
+        SourcePack{..}  <- askSalak
+        as <- trace (show source) $ require "array"
         cf <- require "me.icymint.conf"
         lift $ do
           as      `shouldBe` ["a","b","d","c" :: String]
diff --git a/test/salak.yml b/test/salak.yml
--- a/test/salak.yml
+++ b/test/salak.yml
@@ -6,8 +6,7 @@
 hello:
   world
 a:
-  b:
-    c
+  b: c
 
 me.icymint.conf:
   name: daniel
@@ -15,3 +14,7 @@
   male: yes
   det:
     hello: abc
+
+xyz:
+  - bcd: hello
+  - bcd: world