[Haskell-beginners] latest Haskell Platform build fails

[Mateusz Kowalczyk]

On 10/18/2014 01:16 PM, Michael Martin wrote:
> 
> On 10/18/2014 02:31 AM, Heinrich Apfelmus wrote:
>> 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
>>
>> -- 
>> http://apfelmus.nfshost.com
>>
> Thanks, Heinrich.
> 
> I find it astonishing that build/install fails because it finds that a 
> dependency that it needs is already
> installed. This is totally unreasonable. I was really looking forward to 
> experimenting with Cloud Haskell,
> but the pain of installation, coupled with Haskell's well-known issues 
> with "dependency hell", have
> soured me on Haskell. The language itself is amazing - I really like it. 
> But I'm afraid that the dysfunctional
> nature of the Haskell ecosystem is driving me back to Erlang/OTP. OTP 
> has proven to be industrial
> strength. I hope that someday (soon), Haskell will be able to claim 
> that, as well.
> 

Why don't you use [1] instead of getting the source binary and finding
yourself struggling? It comes with GHC.

[1]: http://www.haskell.org/platform/linux.html#binary


-- 
Mateusz K.