find_trans_deps.nix

with (import <nixpkgs> {});
with pkgs.lib;
let
  getLicense = meta: 
    if !(meta ? license) then
      "not specified"
    else 
      if (meta.license ? fullName)
      then meta.license.fullName
      else 
        if (isList meta.license)
        then map (l: l.fullName) meta.license
        else meta.license;

  package = pkgs.${builtins.getEnv("PACKAGE")};
  showPkg = pkg: { 
    name = pkg.name;
    path = toString pkg;
    license = getLicense pkg.meta;
  };
  computeDeps = pkg: [(showPkg pkg)] ++ (map (x: computeDeps x) pkg.nativeBuildInputs);
in
{
 packagePath = toString package;
 depList = computeDeps package;
}

find_trans_deps.rb

require "json"
require "pp"
package_name = "vim"

nix_info = JSON.load `PACKAGE=#{package_name} nix-instantiate --strict --json --eval find_trans_deps.nix`

runtime_deps = `nix-store -qR #{nix_info["packagePath"]}`.split("\n")

pp nix_info

pp runtime_deps

output.txt

[maarten@maarten-laptop:~/code/nixos]$ ruby find_trans_deps.rb 
{"depList"=>
  [{"license"=>"Vim License",
    "name"=>"vim-7.4.2367",
    "path"=>"/nix/store/g0dnigcj3xp8dag353wqwal4lv4jk83w-vim-7.4.2367"},
   [{"license"=>"not specified",
     "name"=>"gettext-0.19.8",
     "path"=>"/nix/store/iqh4fn2hbg33rsnyqb5fsmj40wny6h1f-gettext-0.19.8"},
    [{"license"=>
       ["GNU General Public License v2.0 or later",
        "GNU Library General Public License v2.1 or later"],
      "name"=>"xz-5.2.2",
      "path"=>"/nix/store/xdppv5b3ag803vkan6dcm9wxzryv0zxs-xz-5.2.2-dev"}],
    [{"license"=>
       ["GNU General Public License v2.0 or later",
        "GNU Library General Public License v2.1 or later"],
      "name"=>"xz-5.2.2",
      "path"=>"/nix/store/cksisynf1z4h4n6xp132aynhqxjqscp8-xz-5.2.2-bin"}]],
   [{"license"=>"MIT License",
     "name"=>"ncurses-6.0",
     "path"=>"/nix/store/h138nb121m5xqrgl2sf4drndgwmgijjc-ncurses-6.0-dev"},
    [{"license"=>"not specified",
      "name"=>"pkg-config-0.29",
      "path"=>"/nix/store/mc1566sppzfqsggxcqckvxamk989pr9h-pkg-config-0.29"}]],
   [{"license"=>"not specified",
     "name"=>"pkg-config-0.29",
     "path"=>"/nix/store/mc1566sppzfqsggxcqckvxamk989pr9h-pkg-config-0.29"}]],
 "packagePath"=>"/nix/store/g0dnigcj3xp8dag353wqwal4lv4jk83w-vim-7.4.2367"}
["/nix/store/27binbdy296qvjycdgr1535v8872vz3z-glibc-2.24",
 "/nix/store/2c1jp8rzbb40h3xkan5z1w7bzrlqy065-bash-4.3-p48",
 "/nix/store/51qrnwwwgv39vffnxn8zgap3dw39x5mx-gawk-4.1.3",
 "/nix/store/mpva72r712z5j36ls5a2d72a0da053n8-ncurses-6.0",
 "/nix/store/g0dnigcj3xp8dag353wqwal4lv4jk83w-vim-7.4.2367"]