Don Stewart wrote: > If I understand correctly, the main issue for Udo is simply that the > MonadFix instance is required by his code, and isn't available in binary > 0.3 -- the version to be used on earlier GHCs. Is that right Udo?
No, the issue is that nothing works. It turns out that I actually wanted the MonadFix instance for something unrelated, only at about the same time (and using runGetState, I can even work around that if I want). Here's the story of how not to intall tar-1.0 on GHC 6.4: - I'm on a Ubuntu system, GHC 6.4 has been installen from .deb packages, my local GHC config is empty. - I unpack tar-1.0 and try to run "Setup configure" on it => module "Distribution.Simple" does not export "UserHooks(confHook)" - I need a more recent cabal, my choice is cabal-1.1.6.2, which install flawlessly. - back to tar-1.0 => base >= 2.0 is required, => unix-1.0 is used for unix-any This is already messed up, tar wants unix-compat, not unix-any. (Or is it? See below.) Apparently, it is a fatal error to have a dash in any package name. This explains why System.PosixCompat will never be found, no matter how often I install it. - Since binary is also needed, I'll now install binary-0.3 => could not find module "Data.ByteString" - So I need ByteString. It is not in Hackage. Googling around leads me to http://www.cse.unsw.edu.au/~dons/fps.html, where I download fps-0.7, since fps is what binary.cabal mentions in a comment. - fps-0.7 install flawlessly. - back to building binary => constructor LPS is not found - no newer fps is available, I get bytestring from darcs - bytestring wants a newer cabal. But my patience is already running out, so instead I edit the cabal file, and it installs. - back to building binary => module "Data.ByteString.Base" not found At this point I'm fed up, delete the whole setup and go back to the one I already hacked up to work with binary-0.4. Getting binary-0.4 and hammering it into shape to run on GHC 6.4 would have been the next step anyway, and after that, tar-1.0 needs to be edited to refer to System.Posix and then it would probably work. I dimply remember that it was also impossible to install unix-compat because the wrong cabal was picked up and I ended up throwing out unix-compat completely. Okay, summarizing, what did cabal do for me? Well, it helped me install a new version of cabal and an obsolete version of something else. Sorry, but this whole experience is a huge turnoff. With things going that smoothly, I'm better off using ghc --make and distributing the stuff I cannot rely on directly with my code. Now here's the story for GHC 6.6: - I'm on Debian testing, GHC 6.6.1 is installed, cabal is 1.1.6.2. I'm in a fresh user account without local additions to GHC. - download tar-1.0, unpack and configure. Binary is needed. - download binary-0.3, installs flawlessly. - back to tar-1.0. Now this is weird: => Dependency unix-any: using unix-2.1 => cannot satisfy dependency unix-compat>=0.1 Why does it want *both* unix and unix-compat? The .cabal file mentions only one of them, unix-compat. - download unix-compat, installs flawlessly. - tar works now So things look a lot better on GHC 6.6, but only because I used binary-0.3 instead of 0.4, and I did this only because Don recently mentioned it. Suppose I tried binary-0.4 (because I want 'instance MonadFix Get' or because I don't know better): - dependencies on split base cannot be fulfilled. I have to edit the cabal file. - bytestring needs to be updated - a new cabal is needed - the description of base has to be patched to remove the conflict with base - binary-0.4 installs now - try to configure tar-1.0 => Could not find module `Distribution.Setup' This is no fun at all. Not only do I have to work around the incompatible changes in base, the interface of Cabal also changed in an incompatible way. -Udo -- My teachers could easily have ridden with Jesse James for all the time they stole from me. -- Richard Brautigan
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