Bump nixpkgs and simplify/clean up nix setup (#1529)

* Refactor tests and fix README

* fix linting hints from new hlint version

* postgrest-style with new nixpkgs-fmt

src/PostgREST/App.hs

@@ -82,7 +82,7 @@ postgrest conf refDbStructure pool getTime worker =
           -- Need to parse ?columns early because findProc needs it to solve overloaded functions.
           -- TODO: move this logic to the app function
           let apiReq = userApiRequest (configSchemas conf) (configRootSpec conf) req body
-              apiReqCols = (,) <$> apiReq <*> (pRequestColumns =<< iColumns <$> apiReq)
+              apiReqCols = (,) <$> apiReq <*> (pRequestColumns . iColumns =<< apiReq)
           case apiReqCols of
             Left err -> return . errorResponseFor $ err
             Right (apiRequest, maybeCols) -> do

src/PostgREST/Config.hs

@@ -164,7 +164,7 @@ readOptions = do
         <*> (fmap unpack <$> optString "server-unix-socket")
         <*> parseSocketFileMode "server-unix-socket-mode"
         <*> (fmap encodeUtf8 <$> optString "jwt-secret")
-        <*> (fromMaybe False <$> optBool "secret-is-base64")
+        <*> ((Just True ==) <$> optBool "secret-is-base64")
         <*> parseJwtAudience "jwt-aud"
         <*> (fromMaybe 10 <$> optInt "db-pool")
         <*> (fromMaybe 10 <$> optInt "db-pool-timeout")

src/PostgREST/Parsers.hs

@@ -229,7 +229,7 @@ pLogicSingleVal = try (pQuotedValue <* notFollowedBy (noneOf ",)")) <|> try pPgA
       a <- string "{"
       b <- many (noneOf "{}")
       c <- string "}"
-      toS <$> pure (a ++ b ++ c)
+      pure (toS $ a ++ b ++ c)
 
 pLogicPath :: Parser (EmbedPath, Text)
 pLogicPath = do

src/PostgREST/RangeQuery.hs

@@ -99,5 +99,5 @@ contentRangeH lower upper total =
         | totalNotZero && fromInRange = show lower <> "-" <> show upper
         | otherwise = "*"
       totalString   = maybe "*" show total
-      totalNotZero  = maybe True (0 /=) total
+      totalNotZero  = Just 0 /= total
       fromInRange   = lower <= upper