Hi, Just to inform everyone, I've got Data.Map and Data.Set going through with Yhc, so maybe self-compiling isn't as far away as everyone (i.e. Me) thought :) The things that are required to get the haskell.org libraries working are: 1) Directory, which requires FFI (Tom is working on this) 2) Delete haskell98 package supplied with Yhc, most of this is in the haskell.org haskell98 package, which needs setting up (should be easy) (I will do this, after the other steps) 3) Move all the heirarchial stuff in yhc-base to Yhc.Internal.* - absolutely everything must go in that namespace, including Prelude etc. Some of the modules want to die (Data.Maybe) some just need moving. Moving most should be easy, moving Prelude will probably be hard. (I will probably need Tom's help for this) 4) Modify the haskell.org base package to be Yhc compatible, the changes should be minimal. In particular Prelude will need to import Yhc.Internal.Prelude. I have some rough patches, some features required and just some general maintenance required. (Some bits are going to be Tom's domain, I can do the rest). This will make haskell98, base and yhc-base all required packages for a default Yhc installation, and all required to build Yhc itself. Thanks Neil