
I have a very basic usage pattern and installation on a few machines, and yet continually run into the often discussed cabal-maze of problems on all of them. I have read all of the many explanations of why it is a hard problem, but so far the only solution I have heard for repair is to erase the installed library files, and start over. This can be hard if one has any external libraries installed which were themselves a lot of work to get functioning, an example are graphics libraries (like WxWin). Has anyone created any scripts which would note everything which is installed, clear out all libraries, and then try to re-install everything? (This is on Windows....) Or would this typically just run into the same problems? Doing a cabal update, it notes a new version of cabal -install, so trying that fails, and now it looks like cabal itself is broken (no installs work). Any short-term \remedies, and/or long term better approaches?
cabal update Downloading the latest package list from hackage.haskell.org Skipping download: Local and remote files match. Note: there is a new version of cabal-install available. To upgrade, run: cabal install cabal-install
cabal install cabal-install Resolving dependencies... cabal: Could not resolve dependencies: trying: Cabal-1.20.0.2/installed-a16... (user goal) trying: ghc-syb-utils-0.2.3/installed-f83... (user goal) next goal: ghc (dependency of ghc-syb-utils-0.2.3/installed-f83...) rejecting: ghc-7.8.3/installed-a4e... (conflict: Cabal==1.20.0.2/installed-a16..., ghc => Cabal==1.18.1.3/installed-421...) rejecting: ghc-7.4.2/installed-4d6... (conflict: ghc-syb-utils => ghc==7.8.3/installed-a4e...) Backjump limit reached (change with --max-backjumps).
Note: when using a sandbox, all packages are required to have consistent dependencies. Try reinstalling/unregistering the offending packages or recreating the sandbox.

On Fri, 30 Jan 2015 14:54:36 +0100, Gregory Guthrie
Doing a cabal update, it notes a new version of cabal -install, so trying that fails, and now it looks like cabal itself is broken (no installs work). Any short-term \remedies, and/or long term better approaches?
A method that usually works is as follows: md CabalInstall cd CabalInstall cabal sandbox init cabal install cabal-install Then copy CabalInstall\.cabal-sandbox\bin\cabal.exe to the location of the old cabal.exe (probably something like "C:\Program Files\Haskell Platform\2014.2.0.0\lib\extralibs\bin\" (Maybe rename the old cabal.exe to cabal-1.20.0.4.exe (or something similar) first) Check with cabal --version if the correct version of cabal.exe is run. If you are using a sandbox, all locally installed packages are ignored, so there is less chance of dependency problems. Regards, Henk-Jan van Tuyl -- Folding@home What if you could share your unused computer power to help find a cure? In just 5 minutes you can join the world's biggest networked computer and get us closer sooner. Watch the video. http://folding.stanford.edu/ http://Van.Tuyl.eu/ http://members.chello.nl/hjgtuyl/tourdemonad.html Haskell programming --

If you're on Windows install development environments outside the Programs
Folder which has special protections on it.
--
--
Sent from an expensive device which will be obsolete in a few months! :D
Casey
On Jan 30, 2015 2:33 PM, "Henk-Jan van Tuyl"
On Fri, 30 Jan 2015 14:54:36 +0100, Gregory Guthrie
wrote: Doing a cabal update, it notes a new version of cabal -install, so trying
that fails, and now it looks like cabal itself is broken (no installs work). Any short-term \remedies, and/or long term better approaches?
A method that usually works is as follows: md CabalInstall cd CabalInstall cabal sandbox init cabal install cabal-install Then copy CabalInstall\.cabal-sandbox\bin\cabal.exe to the location of the old cabal.exe (probably something like "C:\Program Files\Haskell Platform\2014.2.0.0\lib\extralibs\bin\" (Maybe rename the old cabal.exe to cabal-1.20.0.4.exe (or something similar) first) Check with cabal --version if the correct version of cabal.exe is run.
If you are using a sandbox, all locally installed packages are ignored, so there is less chance of dependency problems.
Regards, Henk-Jan van Tuyl
-- Folding@home What if you could share your unused computer power to help find a cure? In just 5 minutes you can join the world's biggest networked computer and get us closer sooner. Watch the video. http://folding.stanford.edu/
http://Van.Tuyl.eu/ http://members.chello.nl/hjgtuyl/tourdemonad.html Haskell programming -- _______________________________________________ Beginners mailing list Beginners@haskell.org http://www.haskell.org/mailman/listinfo/beginners
participants (3)
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Gregory Guthrie
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Henk-Jan van Tuyl
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KC