instance IsList Builder

haskell · Apr 12, 2024 · 5855a0e · 5855a0e
1 parent 46a3aeb
commit 5855a0e
Showing 1 changed file with 9 additions and 0 deletions.
diff --git a/Data/ByteString/Builder/Internal.hs b/Data/ByteString/Builder/Internal.hs
@@ -1,4 +1,6 @@
 {-# LANGUAGE Unsafe #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE NoMonoLocalBinds #-}
 
 {-# OPTIONS_HADDOCK not-home #-}
 
@@ -128,6 +130,7 @@ module Data.ByteString.Builder.Internal (
 ) where
 
 import           Control.Arrow (second)
+import           GHC.Exts (IsList(..))
 
 import           Data.Semigroup (Semigroup(..))
 import           Data.List.NonEmpty (NonEmpty(..))
@@ -414,6 +417,12 @@ instance Monoid Builder where
   {-# INLINE mconcat #-}
   mconcat = foldr mappend mempty
 
+instance IsList Builder where
+  type Item Builder = Word8
+  fromList = byteStringInsert . fromList
+  fromListN n = byteStringThreshold n . fromList
+  toList = toList . toLazyByteStringWith (safeStrategy L.smallChunkSize L.smallChunkSize) mempty
+
 -- | Flush the current buffer. This introduces a chunk boundary.
 {-# INLINE flush #-}
 flush :: Builder