diff --git a/Z-YAML.cabal b/Z-YAML.cabal
--- a/Z-YAML.cabal
+++ b/Z-YAML.cabal
@@ -1,6 +1,6 @@
 cabal-version:              >=1.10
 name:                       Z-YAML
-version:                    0.1.0.0
+version:                    0.2.0.0
 synopsis:                   YAML tools
 description:                YAML reading & writing tools for Z project.
 license:                    BSD3
@@ -28,8 +28,8 @@
                             , scientific            == 0.3.*
                             , transformers          == 0.5.*
                             , primitive             >= 0.5 && < 0.8
-                            , Z-Data == 0.2.*
-                            , Z-IO == 0.2.*
+                            , Z-Data == 0.3.*
+                            , Z-IO == 0.3.*
 
 
     include-dirs:           third_party/libyaml/src
diff --git a/Z/Data/YAML.hs b/Z/Data/YAML.hs
--- a/Z/Data/YAML.hs
+++ b/Z/Data/YAML.hs
@@ -11,7 +11,7 @@
 The design choice to make things as simple as possible since YAML is a complex format, there're some limitations using this approach:
 
 * Does not support complex keys.
-* Dose not support multiple doucments in one file.
+* Does not support multiple doucments in one file.
 
 @
 {-# LANGUAGE DeriveGeneric, DeriveAnyClass, DerivingStrategies, TypeApplication #-}
@@ -28,7 +28,7 @@
   deriving (Show, Generic)
   deriving anyclass (YAML.FromValue, YAML.ToValue)
 
-> YAML.decode @[Person] "- name: Erik Weisz\n  age: 52\n  magic: True\n"
+> YAML.decode @[Person] "- name: Erik Weisz\\n  age: 52\\n  magic: True\\n"
 > Right [Person {name = "Erik Weisz", age = 52, magic = True}]
 @
 
@@ -36,7 +36,7 @@
 
 
 module Z.Data.YAML
-  ( -- * decode and encode using YAML
+  ( -- * Decode and encode using YAML
     decodeFromFile
   , decodeValueFromFile
   , decode
@@ -45,14 +45,14 @@
   , encodeValueToFile
   , encode
   , encodeValue
-  , YAMLParseError(..)
   , YAMLParseException(..)
-  -- * streaming parser and builder
+  , YAMLParseError(..)
+  -- * Streaming parser and builder
   , parseSingleDoucment
   , parseAllDocuments
   , buildSingleDocument
   , buildValue
-  -- * re-exports
+  -- * Re-Exports
   , FromValue(..)
   , ToValue(..)
   , Value(..)
@@ -66,6 +66,7 @@
 import qualified Data.HashMap.Strict as HM
 import qualified Data.HashSet        as HS
 import qualified Data.Scientific as Sci
+import           Z.Data.ASCII
 import qualified Z.Data.Parser as P
 import qualified Z.Data.Vector as V
 import qualified Z.Data.Text   as T
@@ -77,7 +78,6 @@
 import           Z.Data.CBytes          (CBytes)
 import           Z.Data.YAML.FFI
 import           Z.IO
-import           System.IO.Unsafe
 
 -- | Decode a 'FromValue' instance from file.
 decodeFromFile :: (HasCallStack, FromValue a) => CBytes -> IO a
@@ -91,15 +91,15 @@
 decodeValueFromFile p = withResource (initFileParser p) parseSingleDoucment
 
 -- | Decode a 'FromValue' instance from bytes.
-decode :: FromValue a => V.Bytes -> Either YAMLParseException a
-decode bs = unsafePerformIO . try . withResource (initParser bs) $ \ src -> do
+decode :: HasCallStack => FromValue a => V.Bytes -> IO a
+decode bs = withResource (initParser bs) $ \ src -> do
     r <- convert' <$> parseSingleDoucment src
     case r of Left e -> throwIO (YAMLConvertException e callStack)
               Right v -> return v
 
 -- | Decode a 'Value' from bytes.
-decodeValue :: V.Bytes -> Either YAMLParseException Value
-decodeValue bs = unsafePerformIO . try $ withResource (initParser bs) parseSingleDoucment
+decodeValue :: HasCallStack => V.Bytes -> IO Value
+decodeValue bs = withResource (initParser bs) parseSingleDoucment
 
 -- | Encode a 'ToValue' instance to file.
 encodeToFile :: (HasCallStack, ToValue a) => YAMLFormatOpts -> CBytes -> a -> IO ()
@@ -112,24 +112,24 @@
     buildSingleDocument sink v
 
 -- | Encode a 'ToValue' instance as UTF8 text.
-encode :: (HasCallStack, ToValue a) => YAMLFormatOpts -> a -> T.Text
-encode opts x = unsafePerformIO . withResource (initEmitter opts) $ \ (p, sink) -> do
+encode :: (HasCallStack, ToValue a) => YAMLFormatOpts -> a -> IO T.Text
+encode opts x = withResource (initEmitter opts) $ \ (p, sink) -> do
     buildSingleDocument sink (toValue x)
     getEmitterResult p
 
 -- | Encode a 'Value' as UTF8 text.
-encodeValue :: HasCallStack => YAMLFormatOpts -> Value -> T.Text
-encodeValue opts v = unsafePerformIO . withResource (initEmitter opts) $ \ (p, sink) -> do
+encodeValue :: HasCallStack => YAMLFormatOpts -> Value -> IO T.Text
+encodeValue opts v = withResource (initEmitter opts) $ \ (p, sink) -> do
     buildSingleDocument sink v
     getEmitterResult p
 
 --------------------------------------------------------------------------------
 
 data YAMLParseError
-    = UnknownAlias Mark Mark Anchor
+    = UnknownAlias MarkedEvent
     | UnexpectedEvent MarkedEvent
-    | NonStringKey Mark Mark T.Text
-    | NonStringKeyAlias Mark Mark Anchor
+    | NonStringKey MarkedEvent
+    | NonStringKeyAlias MarkedEvent
     | UnexpectedEventEnd
   deriving (Show, Eq)
 
@@ -194,14 +194,14 @@
     (_, mref) <- ask
     liftIO $ modifyIORef' mref (HM.insert key value)
 
-lookupAlias :: Mark -> Mark -> T.Text -> ParserIO Value
-lookupAlias startMark endMark key = do
+lookupAlias :: MarkedEvent -> T.Text -> ParserIO Value
+lookupAlias me key = do
     (_, mref) <- ask
     liftIO $ do
         m <- readIORef mref
         case HM.lookup key m of
             Just v -> return v
-            _ -> throwIO (UnknownAlias startMark endMark key)
+            _ -> throwIO (UnknownAlias me)
 
 textToValue :: ScalarStyle -> Tag -> T.Text -> Value
 textToValue SingleQuoted _ t = String t
@@ -222,8 +222,8 @@
       <|> (fromInteger <$> (P.bytes "0o" *> octal))
       <|> P.scientific
 
-    octal = V.foldl' step 0 <$> P.takeWhile1 (\ w -> w >= B.ZERO && w < B.ZERO+8)
-    step a c = (a `unsafeShiftL` 3) .|. fromIntegral (c - B.ZERO)
+    octal = V.foldl' step 0 <$> P.takeWhile1 (\ w -> w >= DIGIT_0 && w < DIGIT_0+8)
+    step a c = (a `unsafeShiftL` 3) .|. fromIntegral (c - DIGIT_0)
 
 parseValue :: MarkedEvent -> ParserIO Value
 parseValue me@(MarkedEvent e startMark endMark) =
@@ -240,7 +240,7 @@
             !v <- parseMapping
             defineAnchor anchor v
             return v
-        EventAlias anchor              -> lookupAlias startMark endMark anchor
+        EventAlias anchor              -> lookupAlias me anchor
         _ -> throwParserIO (UnexpectedEvent me)
 
 parseSequence :: ParserIO Value
@@ -268,13 +268,13 @@
                             k@(String k') -> do
                                 defineAnchor anchor k
                                 return k'
-                            _ -> throwParserIO (NonStringKey startMark endMark v)
+                            _ -> throwParserIO (NonStringKey me)
 
                     EventAlias anchor -> do
-                        m <- lookupAlias startMark endMark anchor
+                        m <- lookupAlias me anchor
                         case m of
                             String k -> return k
-                            _ -> throwParserIO (NonStringKeyAlias startMark endMark anchor)
+                            _ -> throwParserIO (NonStringKeyAlias me)
                     e -> throwParserIO (UnexpectedEvent me)
 
                 value <- parseValue =<< pullEvent
@@ -298,7 +298,6 @@
 
 -- | Write a value as a YAML document stream.
 --
--- @since 0.11.2.0
 buildSingleDocument :: HasCallStack => Sink Event -> Value -> IO ()
 buildSingleDocument sink v = do
     push sink EventStreamStart
@@ -307,9 +306,8 @@
     push sink EventDocumentEnd
     void $ push sink EventStreamEnd
 
--- | Write a value as a list of 'Event's(without document start\/end, stream start\/end).
+-- | Write a value as a stream of 'Event's(without document start\/end, stream start\/end).
 --
--- @since 0.11.2.0
 buildValue :: HasCallStack => Sink Event -> Value -> IO ()
 buildValue sink (Array vs) = do
     push sink (EventSequenceStart "" NoTag AnySequence)
diff --git a/Z/Data/YAML/FFI.hsc b/Z/Data/YAML/FFI.hsc
--- a/Z/Data/YAML/FFI.hsc
+++ b/Z/Data/YAML/FFI.hsc
@@ -49,6 +49,9 @@
     , pattern AnyMapping
     , pattern BlockMapping
     , pattern FlowMapping 
+    , TagRender
+    , pattern Explicit 
+    , pattern Implicit
     -- * Exception type
     , LibYAMLException (..)
     ) where
@@ -71,7 +74,7 @@
 import qualified Z.IO.FileSystem    as FS
 import qualified Z.Data.Vector      as V
 import qualified Z.Data.Text.Base   as T
-import           Z.Data.Text.ShowT  (ShowT)
+import           Z.Data.Text.Print  (Print)
 import           Z.Data.JSON        (EncodeJSON, FromValue, ToValue)
 
 #include "yaml.h"
@@ -90,7 +93,7 @@
     | EventMappingStart   !Anchor !Tag !MappingStyle 
     | EventMappingEnd    
     deriving (Show, Ord, Eq, Generic)
-    deriving anyclass (ShowT, EncodeJSON, FromValue, ToValue)
+    deriving anyclass (Print, EncodeJSON, FromValue, ToValue)
 
 data MarkedEvent = MarkedEvent 
     { markedEvent :: !Event
@@ -98,7 +101,7 @@
     , endMark :: !Mark
     }
     deriving (Show, Ord, Eq, Generic)
-    deriving anyclass (ShowT, EncodeJSON, FromValue, ToValue)
+    deriving anyclass (Print, EncodeJSON, FromValue, ToValue)
 
 -- | The pointer position
 data Mark = Mark 
@@ -107,7 +110,7 @@
     , yamlColumn :: {-# UNPACK #-} !Int 
     }
     deriving (Show, Ord, Eq, Generic)
-    deriving anyclass (ShowT, EncodeJSON, FromValue, ToValue)
+    deriving anyclass (Print, EncodeJSON, FromValue, ToValue)
 
 -- | Style for scalars - e.g. quoted / folded
 -- 
@@ -148,7 +151,7 @@
          | UriTag T.Text
          | NoTag
     deriving (Show, Ord, Eq, Generic)
-    deriving anyclass (ShowT, EncodeJSON, FromValue, ToValue)
+    deriving anyclass (Print, EncodeJSON, FromValue, ToValue)
 
 tagToCBytes :: Tag -> CB.CBytes
 tagToCBytes StrTag = "tag:yaml.org,2002:str"
@@ -226,7 +229,6 @@
             fclose file)
     return bio
 
-
 -- | Parse a single event from YAML parser.
 peekParserEvent :: HasCallStack => Ptr ParserStruct -> IO (Maybe MarkedEvent)
 peekParserEvent parser = do
@@ -494,7 +496,6 @@
     withTag tag = CB.withCBytesUnsafe (tagToCBytes tag)
     withAnchor anchor = CB.withCBytesUnsafe (CB.fromText anchor) 
 
-
 -- | Whether a tag should be rendered explicitly in the output or left
 -- implicit.
 --
@@ -503,7 +504,7 @@
 pattern Explicit = 0
 pattern Implicit = 1
 
--- | A value for 'formatOptionsRenderTags' that renders no
+-- | A value for 'yamlFormatRenderTags' that renders no
 -- collection tags but all scalar tags (unless suppressed with styles
 -- 'NoTag or 'PlainNoTag').
 --
@@ -513,13 +514,13 @@
 renderScalarTags (EventMappingStart _ _ _) = Implicit
 renderScalarTags _ = Implicit
 
--- | A value for 'formatOptionsRenderTags' that renders all
+-- | A value for 'yamlFormatRenderTags' that renders all
 -- tags (except 'NoTag' tag and 'PlainNoTag' style).
 --
 renderAllTags :: Event -> TagRender
 renderAllTags _ = Explicit
 
--- | A value for 'formatOptionsRenderTags' that renders no
+-- | A value for 'yamlFormatRenderTags' that renders no
 -- tags.
 --
 renderNoTags :: Event -> TagRender
diff --git a/cbits/hs_yaml.c b/cbits/hs_yaml.c
--- a/cbits/hs_yaml.c
+++ b/cbits/hs_yaml.c
@@ -15,31 +15,31 @@
 }
 
 typedef struct hs_yaml_buf_s {
-	unsigned char *buf;
-	size_t size;
+    unsigned char *buf;
+    size_t size;
     size_t used;
 } hs_yaml_buf_t;
 
 int buffer_append(void *ext, unsigned char *str, size_t size)
 {
-	hs_yaml_buf_t *b = ext;
-	int new_size, new_used;
-	unsigned char *tmp;
+    hs_yaml_buf_t *b = ext;
+    int new_size, new_used;
+    unsigned char *tmp;
 
-	new_used = b->used + size;
-	for (new_size = b->size ? b->size : 120; new_size < new_used; new_size *= 2);
+    new_used = b->used + size;
+    for (new_size = b->size ? b->size : 120; new_size < new_used; new_size *= 2);
 
-	if (new_size != b->size) {
-		tmp = realloc(b->buf, new_size);
-		if (!tmp) return 0;
-		b->buf = tmp;
-		b->size = new_size;
-	}
+    if (new_size != b->size) {
+        tmp = realloc(b->buf, new_size);
+        if (!tmp) return 0;
+        b->buf = tmp;
+        b->size = new_size;
+    }
 
-	memcpy(b->buf + b->used, str, size);
-	b->used = new_used;
+    memcpy(b->buf + b->used, str, size);
+    b->used = new_used;
 
-	return 1;
+    return 1;
 }
 
 yaml_emitter_t* hs_init_yaml_emitter(int canonical, int indent, int width)
@@ -104,8 +104,8 @@
 
 
 int hs_yaml_sequence_start_event_initialize(yaml_event_t *event,
-        const yaml_char_t *anchor, const yaml_char_t *tag, int implicit,
-        yaml_sequence_style_t style) {
+    const yaml_char_t *anchor, const yaml_char_t *tag, int implicit,
+    yaml_sequence_style_t style) {
 
     if (*anchor == 0) anchor = NULL;
     if (*tag == 0) tag = NULL;
@@ -114,10 +114,10 @@
 
 
 int hs_yaml_scalar_event_initialize(yaml_event_t *event,
-        const yaml_char_t *anchor, const yaml_char_t *tag,
-        const yaml_char_t *value, int off, int length, 
-        int plain_implicit, int quoted_implicit,
-        yaml_scalar_style_t style){
+    const yaml_char_t *anchor, const yaml_char_t *tag,
+    const yaml_char_t *value, int off, int length, 
+    int plain_implicit, int quoted_implicit,
+    yaml_scalar_style_t style){
 
     if (*anchor == 0) anchor = NULL;
     if (*tag == 0) tag = NULL;
@@ -126,8 +126,8 @@
 
 
 int hs_yaml_mapping_start_event_initialize(yaml_event_t *event,
-        const yaml_char_t *anchor, const yaml_char_t *tag, int implicit,
-        yaml_mapping_style_t style) {
+    const yaml_char_t *anchor, const yaml_char_t *tag, int implicit,
+    yaml_mapping_style_t style) {
 
     if (*anchor == 0) anchor = NULL;
     if (*tag == 0) tag = NULL;
@@ -135,10 +135,5 @@
 }
 
 int hs_yaml_document_start(yaml_event_t *e) {
-	return yaml_document_start_event_initialize
-		(e,
-		 0,
-		 0,
-		 0,
-		 1);
+    return yaml_document_start_event_initialize(e, 0, 0, 0, 1);
 }