errorsCleanup.hs

seriousBusiness :: Trans IO Int
seriousBusiness = do
  res1 <- doSomeAction
  cleanupOnErrors res1 $ do
    res2 <- doOtherAction
    cleanupOnErrors res2 $ do
      res3 <- doEvenMoreAction
      cleanupOnErrors res3 $ do
        return 42

cleanupOnErrors :: (MonadCatch m) => Res -> m a -> m a
cleanupOnErrors res ma = catchAll ma $ \e -> do
  cleanupRes res
  throwM e