[Nix-dev] Proper way of adding custom nix expressions

[Andres Loeh]

Hi Richard.

> pkgs : {
  ^^^^

You refer to this argument ...

>   packageOverrides = self : rec {
                       ^^^^

but you should refer to this one.

>     myHaskellPackages =
>       let callPackage = pkgs.lib.callPackageWith myHaskellPackages; in
>         pkgs.haskellPackages.override {
>           extraPrefs = self : {
>             boomerang = callPackage ./haskell/boomerang.nix {};
>           };
>         };
>   };
> }

Cheers,
  Andres