Hello John, Tuesday, February 07, 2006, 4:23:36 AM, you wrote: data Eq a => Set a = Set (List a) that is a sort of extension i will be glad to see. in my Streams library, it's a typical beast and i forced to move all these contexts to the instances/functions definitions: data BufferedMemoryStream h = MBuf {-MemoryStream-} h ... -- | Create BufferedMemoryStream from any MemoryStream bufferMemoryStream :: (MemoryStream IO h) => h -> IO (BufferedMemoryStream h) instance (MemoryStream IO h) => Stream IO (BufferedMemoryStream h) where with RDT, that should shorten to the: data (MemoryStream IO h) => BufferedMemoryStream h = MBuf h ... bufferMemoryStream :: h -> IO (BufferedMemoryStream h) instance Stream IO (BufferedMemoryStream h) where what the Hugs ang GHC implementors think about this extension? -- Best regards, Bulat mailto:bulatz@HotPOP.com