[Nix-dev] overriding a package

[Bjørn Forsman]

On 31 January 2015 at 16:07, Catonano <catonano at gmail.com> wrote:
> I am following this guide to override a package
>
> https://nixos.org/wiki/Nix_Modifying_Packages#Overriding_Existing_Packages
>
> I copied and pasted the example about the "mu" and "mySed" packages and I
> ended up with this
>
>
>
>     {
>      packageOverrides = pkgs: rec {
>
>        # Create a new package, "myDrRacket", which is identical to an
>        #   existing package, "racket", but uses a different version.
>        myRacket = pkgs.stdenv.lib.overrideDerivation pkgs.racket (oldAttrs:
> {
>          pname = "InfTaRacket";
>      version = "6.1.1.8";
>      #name = "${pname}-${version}";
>          src = fetchurl {
>            url =
> http://www.cs.utah.edu/plt/snapshots/current/installers/racket-6.1.1.8-src.tgz;
>            sha256 =
> "c9b4b634cdda62841739ed41179ed3daf42b7231cd024d8d3a7b39cfe0e44fc3";
>          };
>          patches = [];
>        });
>      };
>    }
>
> The result is
>
> nix-env -i InfTaRacket
> error: undefined variable ‘fetchurl’ at "/home/me/.nixpkgs/config.nix":14:16

Try pkgs.fetchurl instead.

Best regards,
Bjørn Forsman