*System.Console.Regions T> genLineUpdate  $ calcLineUpdate (T.pack "\ESC[92mfoofoofoo\ESC[91mbarbarbar\ESC[0mbaz") (T.pack "\ESC[92mfoofoofoo\ESC[91mxarbarbax\ESC[0mbaz")
"\ESC[92m\ESC[91m\ESC[9Cx\ESC[7Cx"

\o/ worked first try!