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

[Peter Simons]

Hi Mateusz,

 > A related question: is there a way to generate a package list containing
 > exactly the versions of dependencies we require?
 >
 > Say we have a package with cabal file
 >
 > A == 1.0
 > B > 2.0
 > C < 0.5
 >
 > but the latest Hackage has versions lower and higher &c and that's what
 > is in nixpkgs. I found myself wishing that there was an easy to just say
 > ‘give me a set of packages that's valid from cabal's point of view’.

What's wrong with

  $ cabal sandbox init
  $ cabal install --only-dependencies

...?

Best regards,
Peter