[Haskell-cafe] Problems installing the haskell platform

[Henry Laxen]

Dear Group,

Greetings.  I've been using haskell for about a year now, though I
will readily admit I still don't really know what I am doing when I
get error messages.  Today I decided to reset my haskell environment
from scratch, avoiding the debian packages and going straight to the
source.



1. Install ghc from http://www.haskell.org/ghc/download_ghc_6_12_3

Success!!

    ghc --version
    The Glorious Glasgow Haskell Compilation System, version 6.12.3

    cabal update
    Downloading the latest package list from hackage.haskell.org

2. Next I downloaded the haskell platform and ran cabal install
Problems!!

    cabal: Error: some packages failed to install:
    haskell-platform-2010.2.0.0 depends on stm-2.1.2.1 which failed to
install.
    stm-2.1.2.1 failed during the building phase. The exception was:
    ExitFailure 1

3. So I tried installing stm manually, which for some unknown reason
worked:

    runghc Setup.hs install
    Installing library in /usr/local/lib/stm-2.1.2.1/ghc-6.12.3
    Registering stm-2.1.2.1...

4. back to the haskell-platform directory and try again:

    cabal install
    Resolving dependencies...
    Configuring haskell-platform-2010.2.0.0...
    setup: happy version ==1.18.5 is required but the version found at
    /usr/local/bin/happy is version 1.18.6
    cabal: Error: some packages failed to install:
    haskell-platform-2010.2.0.0 failed during the configure step. The
exception
    was:
    ExitFailure 1

5. Crap.  Okay, maybe it will work with version 1.18.6 after all, so I
edit the .cabal and change happy ==1.18.5 to happy >=1.18.5

  -- Depending on programs does not work, they are not registered
  -- We list them to help distro packaging.
  build-tools:
    cabal-install ==0.8.2,
    alex          ==2.3.3,
    happy         >=1.18.5
    -- haddock       ==2.7.2 -- valid, but needs ghc-paths

6. Try again

    cabal install
    Resolving dependencies...
    Configuring haskell-platform-2010.2.0.0...
    Preprocessing library haskell-platform-2010.2.0.0...
    Building haskell-platform-2010.2.0.0...
    Registering haskell-platform-2010.2.0.0...
    Installing library in /usr/local/lib/haskell-platform-2010.2.0.0/
ghc-6.12.3
    Registering haskell-platform-2010.2.0.0...

7. Success!!

Now even though I'm not sure what I am doing, it looks like it may
have worked.  I'm worried, though, about the first time user who tries
to go through this process.  They will probably stop at the first
error, when the haskell-platform fails to install.

I know some of you will say use the debian packages.  Well I did that,
but when I tried to install snap, which is not included in the debian
packages, I wound up with conflicting dependencies, and could not find
a way out.  I hope this dialog is helpful to whomever is in charge of
the haskell platform, a wonderful resource by the way.

Best wishes,
Henry Laxen