[Haskell-beginners] Beginner trying to install Haskell support in Eclipse and failing

[Daniel Fischer]

Am Sonntag 18 April 2010 01:07:17 schrieb Alan Shaw:
> Hi,
> I'm using cabal for the first time, and I'm confused.
>
> I'm trying to build scion as instructed at
> http://eclipsefp.sourceforge.net/build.html .
> I have done:
>
> git clone git://github.com/JPMoresmau/scion.git
> cd scion
> cabal install
>
>
> I'm now at the point where this tells me the following:
>
> Resolving dependencies...
> cabal.exe: dependencies conflict: ghc-6.10.4 requires Cabal ==1.6.0.3
> however
> Cabal-1.6.0.3 was excluded because scion-0.1.0.2 requires Cabal ==1.8.*
> && ==1.8.*

That's odd, the .cabal file says

  if flag(cabal_1_8)
    build-depends:  Cabal == 1.8.*
    cpp-options:    -DCABAL_VERSION=108
  else
    build-depends:  Cabal == 1.6.*
    cpp-options:    -DCABAL_VERSION=106

and since you don't have Cabal-1.8.*, it should set the flag to false and 
try again.

Anyway, try setting the flag to false on the command line:

cabal install -f-cabal_1_8

or install the hackage package:

cabal install scion

>
> Some more information:
>
> $ cabal -V
> cabal-install version 0.6.2
> using version 1.6.0.3 of the Cabal library
> $ cabal update
> Downloading the latest package list from hackage.haskell.org
> Note: there is a new version of cabal-install available.
> To upgrade, run: cabal install cabal-install
> $ cabal install cabal-install
> (lots and lots of output, ending with:)
> Linking dist\build\cabal\cabal.exe ...
> Installing executable(s) in C:\Program Files (x86)\Haskell\bin

Is that directory in your path (and before the directory cabal-
install-0.6.2 is in)?

> $ cabal -V
> cabal-install version 0.6.2
> using version 1.6.0.3 of the Cabal library

perhaps

cabal install cabal-install-0.8.0 (or whatever the latest version working 
on windows is)

>
>
> Help?
>
> Thanks,
> -A