[Haskell-beginners] latest Haskell Platform build fails

[Michael Martin]

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.


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