Use GeneralizedNewtypeDeriving to clean up Source.

O(1) null, and far fewer symbol collisions.

src/Diffing.hs

@@ -52,7 +52,7 @@ breakDownLeavesByWord source = cata replaceIn
   where
     replaceIn info@(Info range categories) (Leaf _) | ranges <- rangesAndWordsInSource range, length ranges > 1 = info :< Indexed (makeLeaf categories <$> ranges)
     replaceIn info syntax = info :< syntax
-    rangesAndWordsInSource range = rangesAndWordsFrom (start range) (Source.toList $ slice range source)
+    rangesAndWordsInSource range = rangesAndWordsFrom (start range) (toString $ slice range source)
     makeLeaf categories (range, substring) = Info range categories :< Leaf (T.pack substring)
 
 -- | Transcode a file to a unicode source.

src/Parser.hs

@@ -42,10 +42,10 @@ termConstructor :: (String -> Set.Set Category) -> Constructor
 termConstructor mapping source range name = (Info range categories :<) . construct
   where
     categories = mapping name
-    construct [] = Leaf . pack . toList $ slice range source
+    construct [] = Leaf . pack . toString $ slice range source
     construct children | isFixed categories = Fixed children
     construct children | isKeyed categories = Keyed . Map.fromList $ assignKey <$> children
     construct children = Indexed children
     assignKey node@(Info _ categories :< Fixed (key : _)) | Set.member Pair categories = (getSubstring key, node)
     assignKey node = (getSubstring node, node)
-    getSubstring (Info range _ :< _) = pack . toList $ slice range source
+    getSubstring (Info range _ :< _) = pack . toString $ slice range source

src/Renderer/JSON.hs

@@ -20,7 +20,7 @@ import Diff
 import Line
 import Range
 import Renderer
-import Source hiding (fromList, toList)
+import Source hiding (fromList)
 import SplitDiff
 import Syntax
 import Term

src/Renderer/Patch.hs

@@ -102,7 +102,7 @@ header blobs hunk = intercalate "\n" [filepathHeader, fileModeHeader, beforeFile
 
 -- | Render a diff as a series of hunks.
 hunks :: Renderer a [Hunk (SplitDiff a Info)]
-hunks _ blobs | Both (True, True) <- Source.null . source <$> blobs = [Hunk { offset = mempty, changes = [], trailingContext = [] }]
+hunks _ blobs | Both (True, True) <- null . source <$> blobs = [Hunk { offset = mempty, changes = [], trailingContext = [] }]
 hunks diff blobs = hunksInRows (Both (1, 1)) $ fmap (fmap Prelude.fst) <$> splitDiffByLines (source <$> blobs) diff
 
 -- | Given beginning line numbers, turn rows in a split diff into hunks in a

src/Source.hs

@@ -1,10 +1,12 @@
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
 module Source where
 
-import Range
-import qualified Data.Vector as Vector
+import Data.Foldable
 import qualified Data.Text as T
+import qualified Data.Vector as Vector
 import Data.Word
 import Numeric
+import Range
 
 data SourceKind = PlainBlob Word32  | ExecutableBlob Word32 | SymlinkBlob Word32
   deriving (Show, Eq)
@@ -23,7 +25,7 @@ defaultPlainBlob = PlainBlob 0o100644
 
 -- | The contents of a source file, backed by a vector for efficient slicing.
 newtype Source a = Source { getVector :: Vector.Vector a  }
-  deriving (Eq, Show, Functor, Traversable)
+  deriving (Eq, Show, Foldable, Functor, Traversable)
 
 -- | Return a Source from a list of items.
 fromList :: [a] -> Source a
@@ -33,10 +35,6 @@ fromList = Source . Vector.fromList
 fromText :: T.Text -> Source Char
 fromText = Source . Vector.fromList . T.unpack
 
--- | Return a list of items with the contents of the Source.
-toList :: Source a -> [a]
-toList = Vector.toList . getVector
-
 -- | Return a Source that contains a slice of the given Source.
 slice :: Range -> Source a -> Source a
 slice range = Source . Vector.slice (start range) (rangeLength range) . getVector
@@ -49,17 +47,13 @@ toString = toList
 at :: Source a -> Int -> a
 at = (Vector.!) . getVector
 
--- | Test whether the source is empty.
-null :: Source a -> Bool
-null = Vector.null . getVector
-
 -- | Prepend an item.
 cons :: a -> Source a -> Source a
 cons a = Source . Vector.cons a . getVector
 
 -- | Remove the first item and return it with the rest of the source.
 uncons :: Source a -> Maybe (a, Source a)
-uncons (Source vector) = if Vector.null vector then Nothing else Just (Vector.head vector, Source $ Vector.tail vector)
+uncons (Source vector) = if null vector then Nothing else Just (Vector.head vector, Source $ Vector.tail vector)
 
 -- | Split the source into the longest prefix of elements that do not satisfy the predicate and the rest without copying.
 break :: (a -> Bool) -> Source a -> (Source a, Source a)
@@ -71,7 +65,7 @@ break predicate (Source vector) = let (start, remainder) = Vector.break predicat
 
 -- | Split the contents of the source after newlines.
 actualLines :: Source Char -> [Source Char]
-actualLines source | Source.null source = [ source ]
+actualLines source | null source = [ source ]
 actualLines source = case Source.break (== '\n') source of
   (l, lines') -> case uncons lines' of
     Nothing -> [ l ]
@@ -81,7 +75,3 @@ actualLines source = case Source.break (== '\n') source of
 actualLineRanges :: Range -> Source Char -> [Range]
 actualLineRanges range = drop 1 . scanl toRange (Range (start range) (start range)) . actualLines . slice range
   where toRange previous string = Range (end previous) $ end previous + length string
-
-instance Foldable Source where
-  foldMap f = foldMap f . getVector
-  length = Vector.length . getVector

src/TreeSitter.hs

@@ -16,7 +16,7 @@ treeSitterParser :: Language -> Ptr TS.Language -> Parser
 treeSitterParser language grammar contents = do
   document <- ts_document_make
   ts_document_set_language document grammar
-  withCString (toList contents) (\source -> do
+  withCString (toString contents) (\source -> do
     ts_document_set_input_string document source
     ts_document_parse document
     term <- documentToTerm (termConstructor $ categoriesForLanguage language) document contents