modifyRegionB :: (R.YiString -> R.YiString)
                 -- ^ The string modification function
              -> Region
                 -- ^ The region to modify
              -> BufferM ()
modifyRegionB f region = f <$> readRegionB region >>= replaceRegionB region
modifyRegionB :: (R.YiString -> R.YiString)
                 -- ^ The string modification function
              -> Region
                 -- ^ The region to modify
              -> BufferM ()
modifyRegionB f region = f <$> readRegionB region >>= replaceRegionB region
modifyRegionB f region = f <$> readRegionB region >>= replaceRegionB region