[Haskell-beginners] latest Haskell Platform build fails

[Heinrich Apfelmus]

Michael L Martin wrote:
> On 10/16/2014 03:11 PM, Mateusz Kowalczyk wrote:
>> Merely going from the error message and your steps, it seems to me that
>> you're *not* meant to install GHC yourself first and that the platform
>> ships with GHC. I would say try again but without installing GHC and
>> cabal first.
>>
>>
> Well, that didn't work, either:
> 
> mmartin at cloud:~/Downloads/haskell-platform-2014.2.0.0$ ./platform.sh 
> .../ghc-7.8.3-x86_64-unknown-linux-deb7.tar.bz2
> ../platform.sh: 18: ./platform.sh: cabal: not found
> ***
> *** Building hptool
> ***
> ../platform.sh: 29: ./platform.sh: cabal: not found
> mmartin at cloud:~/Downloads/haskell-platform-2014.2.0.0$

Apparently, different distributions of the Haskell Platform differ in 
what tools they package: the binary distribution includes GHC and cabal, 
whereas the source distribution, which you are currently trying to 
install, doesn't include GHC and cabal.

Judging from the error message

 > Stderr:
 > mtl-2.1.3.1: package(s) with this id already exist: mtl-2.1.3.1

it seems that the platform tries to build the `mtl` package, but fails 
because it is already installed. You can use the command

     $ ghc-pkg list

to see which packages are installed globally and in your home directory. 
Most likely, `mtl` got installed because you installed `cabal-install`. 
I have no idea how to deal with the conflict, though, I'm not really 
familiar with the Haskell platform source distribution.


Best regards,
Heinrich Apfelmus

--
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