Document the declarations in Source.hs

src/Source.hs

@@ -5,42 +5,55 @@ import Range
 import qualified Data.Vector as Vector
 import qualified Data.Text as T
 
+-- | 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, Foldable, Traversable)
 
+-- | Return a Source from a list of items.
 fromList :: [a] -> Source a
 fromList = Source . Vector.fromList
 
+-- | Return a Source of Chars from a Text.
 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
 
+-- | Return a String with the contents of the Source.
 toString :: Source Char -> String
 toString = toList
 
+-- | Return the item at the given  index.
 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)
 
+-- | 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)
 break predicate (Source vector) = let (start, remainder) = Vector.break predicate vector in (Source start, Source remainder)
 
+-- | Concatenate two sources.
 (++) :: Source a -> Source a -> Source a
 (++) (Source a) = Source . (a Vector.++) . getVector
 
+-- | Split the contents of the source by newlines.
 actualLines :: Source Char -> [Source Char]
 actualLines source | Source.null source = [ source ]
 actualLines source = case Source.break (== '\n') source of