Lurker speaks: I too came to the same conclusion as Michael a long time back; I absolutely love Haskell but sooner or later it seemed to me that the "dependancy hell" would kick in just when you least needed / expected it to. It is the single biggest put off for me now to consider using it.

I too find myself back in Erlang and Prolog these days, and I have begun learning OCaml instead as it offers a lot of things that Haskell seems but without the pure functional venus flytraps of monads, state transformers etc etc. 

Not all jobbing developers are math majors or CS majors, some of us are just mere mortals wishing to use shinier tools for a safer and more rigorous path to freedom from day job hell!

But, SPJ et al.... f* awesome language!
:)
Sean


On 18 October 2014 13:16, Michael Martin <mmartin4242@gmail.com> 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@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@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.



_______________________________________________
Beginners mailing list
Beginners@haskell.org
http://www.haskell.org/mailman/listinfo/beginners

_______________________________________________
Beginners mailing list
Beginners@haskell.org
http://www.haskell.org/mailman/listinfo/beginners