[Nix-dev] A Journey into our brand-new Haskell infrastructure: Part II

[Peter Simons]

Hi Thomas,

 > How would I get older versions of certain packages (e.g. I need
 > optparse-applicative 0.10 for elm-make) into hackage-packages.nix?

by adding "optparse-applicative == 0.10.*" to the 'extraPackages' list at
<https://github.com/NixOS/cabal2nix/blob/master/src/hackage2nix.hs#L153-158>.
This would include 'optparse-applicative_0_10_0' in hackage-packages.nix
the next time it's re-generated.

Best regards,
Peter