I'm using ghc 7.4.1 (from the Ubuntu Precise repository). Don't know if this is relevant but "ghc-pkg list" tells me that I have: /var/lib/ghc/package.conf.d Cabal-1.14.0 directory-1.1.0.2 process-1.1.0.1 ... Mike. From: Yves Parès To: Michael Iles/Ottawa/IBM@IBMCA Cc: haskell-cafe@haskell.org Date: 03/28/2012 05:13 PM Subject: Re: [Haskell-cafe] Can't install snap (problem with syb) Sent by: limestrael@gmail.com It may come from the version of GHC you're using (Cabal version is fixed for one specific GHC version). Which one is it? Le 28 mars 2012 23:05, Michael Iles a écrit : I uninstalled ghc, removed my ~/.cabal directory, reinstalled ghc, then tried to install snap. I get: $ cabal install snap Resolving dependencies... Downloading syb-0.3.6... <command line>: cannot satisfy -package Cabal-1.14.0: Cabal-1.14.0-0338b6f52e6e6a56054371a110e1d79e is unusable due to missing or recursive dependencies: directory-1.1.0.2-8957520ced1fb19160c3a6126dcccfaa process-1.1.0.1-91185c964ab744c1f3cbca1863d2ba45 (use -v for more information) cabal: Error: some packages failed to install: aeson-0.6.0.0 depends on syb-0.3.6 which failed to install. snap-0.8.0.2 depends on syb-0.3.6 which failed to install. syb-0.3.6 failed during the configure step. The exception was: ExitFailure 1 Any ideas? Mike. _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Did you install the haskell-platform package? What is the output of ghc-pkg check? On Wed, Mar 28, 2012 at 5:30 PM, Brandon Allbery wrote:

On Wed, Mar 28, 2012 at 17:05, Michael Iles wrote:

...

I uninstalled ghc, removed my ~/.cabal directory, reinstalled ghc, then tried to install snap. I get:

Did you also remove ~/.ghc? Libraries are actually installed and registered there, not under ~/.cabal. Although this shouldn't be a problem if any Cabal-installed libraries were for a different version of ghc, it's safest to remove both.

-- brandon s allbery allbery.b@gmail.com wandering unix systems administrator (available) (412) 475-9364 vm/sms

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On 12-03-28 06:30 PM, Brandon Allbery wrote:

Did you also remove ~/.ghc? Libraries are actually installed and registered there, not under ~/.cabal.

Reality is less simplistic than that. .ghc has library metadata. .cabal has library files. See my http://www.vex.net/~trebla/haskell/sicp.xhtml and verify, verify, verify. Since GHC simply trusts its metadata (and not re-scan library files to re-discover libraries), metadata dominates.