[Nix-dev] Will Haskell-ng and hackage2nix allow building *any* versions of deps?

[Daniel Bergey]

On 2015-02-24 at 23:24, Nikita Karetnikov <nikita at karetnikov.org> wrote:
>> A related question: is there a way to generate a package list containing
>> exactly the versions of dependencies we require?
>
> I asked a similar question but about the cabal.config file some time
> ago.  Here's the response:
>
> http://article.gmane.org/gmane.linux.distributions.nixos/15885

You have now described the two halves of the problem as I understand it:
- get cabal to list a suitable set of particular versions
- get cabal2nix or hackage2nix to generate derivations for specified
versions

hackage2nix now has some very helpful logic to detect name overlap
between haskell packages (usually C bindings) and other libraries.[1]  I'd
be very interested in a way to call hackage2nix on a particular package
version, or set of versions, as we can with cabal2nix, so I can benefit
from this feature.

bergey

Footnotes: 
[1]  https://github.com/NixOS/cabal2nix/blob/master/src/hackage2nix.hs#L180