feat: consistent whitespace + non-empty sepBy

src/Language/Json.hs

@@ -227,6 +227,7 @@ keyValue = do
   val <- value
 
   -- result
+  whitespace
   pure (name, val)
 
 object :: Parser (Map Text Value)
@@ -234,9 +235,10 @@ object = do
   _ <- Parser.char '{'
   whitespace
 
-  members <- (keyValue <* whitespace) `Parser.sepBy` comma
+  members <- keyValue `Parser.sepBy` comma
 
   _ <- Parser.char '}'
+  whitespace
   pure $ Map.fromList members
 
 whitespace :: Parser ()
@@ -250,5 +252,8 @@ array = do
   elements <- value `Parser.sepBy` comma
 
   _ <- Parser.char ']'
-  pure $ Array.listArray (0, fromIntegral $ length elements - 1) elements
+  whitespace
+  pure $ case elements of
+    [] -> Array.listArray (1, 0) elements
+    _  -> Array.listArray (0, fromIntegral $ length elements - 1) elements
 

src/Language/Json/Parser.hs

@@ -88,10 +88,10 @@ times n body = go n
 
 sepBy :: Parser a -> Parser b -> Parser [a]
 sepBy p sep = do
-  first <- p
+  first <- optional p
   rest <- sep *> sepBy p sep <|> pure []
 
-  pure $ first : rest
+  pure $ maybe id (:) first rest
 
 eof :: Parser Bool
 eof = anyChar *> empty <|> pure True