[Haskell] cabal conflicting rules

[Ivan Lazar Miljenovic]

On 25 October 2011 09:34, Ben Millwood <haskell at benmachine.co.uk> wrote:
> Here's the advice I use on when to use what to install cabal packages:
>
> http://www.vex.net/~trebla/haskell/sicp.xhtml
>
> I think it's a bit overcautious, but rather that than the alternative.
> It's worth a read even if you don't follow the advice in the end.

I think the choice of which advice to follows boil down to something
rather simple: how good is the quality of Haskell packages in your
distribution?

My main experience at the time of writing my blog post was with
Gentoo, which had rather good support, especially for the popular
packages (might be a bit behind for not-so-common ones, but easily
bumped if a user asked it).  Quite a few problems then arose with
users trying to mix-and-match system packages with user packages, when
there was no need to do so.

But in distributions that _don't_ have good Haskell support (e.g. I'm
currently using Exherbo, and mix-and-match system and user packages
because the system packages are rather limited; I've been meaning to
try and add native Cabal support to the package manager to fix this
for about a year now, but I'm not looking forward to hacking in C++
:p), then it may make more sense to use user-packages only... _if_ you
understand the limitations this has.

Package managers for distributions are typically better suited for
resolving dependencies (especially if you give them specific
information like "containers isn't meant to be user-upgradeable" and
which version of containers comes with which version of GHC) and are
able to uninstall packages, which cabal-install can't do yet.

-- 
Ivan Lazar Miljenovic
Ivan.Miljenovic at gmail.com
IvanMiljenovic.wordpress.com