Remove some code duplication using Data.Default.

[hs-java.git] / JVM / Common.hs

diff --git a/JVM/Common.hs b/JVM/Common.hs
index 7271e469eabf7cb603af0c54c92125aea4f4c427..65a6c6fcf8425eb1f75e70ed2991c998e495e322 100644 (file)
--- a/JVM/Common.hs
+++ b/JVM/Common.hs
@@ -1,6 +1,12 @@
 {-# LANGUAGE TypeFamilies, StandaloneDeriving, FlexibleInstances, FlexibleContexts, UndecidableInstances #-}
--- | This module declares `high-level' data types for Java classes, methods etc.
-module JVM.Common where
+-- | This module declares some commonly used functions and instances.
+module JVM.Common
+  (toCharList,
+  poolSize,
+  (!),
+  showListIx,
+  byteString
+  ) where
 
 import Codec.Binary.UTF8.String hiding (encode, decode)
 import Data.Binary
@@ -9,9 +15,16 @@ import qualified Data.ByteString.Lazy as B
 import Data.Char
 import Data.String
 import qualified Data.Map as M
+import Data.Default
 
 import JVM.ClassFile
 
+instance Default B.ByteString where
+  def = B.empty
+
+instance Default Word16 where
+  def = 0
+
 instance IsString B.ByteString where
   fromString s = B.pack $ map (fromIntegral . ord) $ encodeString s