Hello Johannes, Friday, October 21, 2005, 11:42:55 AM, you wrote: JW> I'd like to repeat my earlier point that it would be better JW> if the user of the type can decide whether he wants JW> some predefined Show/Read instances or roll his own. JW> http://www.haskell.org/pipermail/libraries/2005-March/003496.html long standing sight...... parameterized modules will be a good solution for all those problems. or ability to hide/import class instances, not only plain functions: import Data.Map hiding (Show(Map)) -- Best regards, Bulat mailto:bulatz@HotPOP.com