[Nix-dev] haskell-ng / cabal-install problem

[Tobias Pflug]

On 07.05.2015 21:22, Peter Simons wrote:
>   nix-build "<nixpkgs>" -A haskell-ng.packages.ghc784.cabal-install

What I need is cabal 1.20.x because I would like to use ghc-mod which
is not compatible with 1.22.x because of a file format change in cabal
leading to ghc-mod being unable to parse.

So how can I install cabal-install 1.20.x? I am on nixpkgs master now
as well.

regards,
Tobi