Example shell.nix for Elixir projects using a preversion

shell.nix

{ pkgs ? import <nixpkgs> {} }:

with pkgs;

let
  elixir_1_7_0_rc_1 = { mkDerivation }:
    mkDerivation rec {
      version = "1.7.0-rc.1";
      # Use `nix-prefetch-github --rev <version> elixir-lang elixir` to update.
      sha256 = "1hp1zdscq7h2qcgcfbzw5dx1wxy05bqlrxvv5kcl8414c69inx8g";
      minimumOTPVersion = "19";
    };

  erl = beam.packages.erlangR21;
  erlang = erl.erlang;
  rebar = erl.rebar;

  elixir = beam.lib.callElixir elixir_1_7_0_rc_1 {
    inherit erlang rebar;
    debugInfo = true;
  };
in

stdenv.mkDerivation {
  name = "test";
  buildInputs = [ elixir ];
}