WIP

pkgs/development/interpreters/ruby/bundix.nix

@@ -0,0 +1,16 @@
+{rubyLibsWith, callPackage, lib}:
+
+{
+  loadRubyEnv = path: config:
+    let
+      expr = callPackage path {};
+      ruby = config.ruby;
+      rubyLibs = rubyLibsWith ruby;
+      gems = rubyLibs.importGems expr.gemset config.gemOverrides;
+    in {
+      inherit ruby; # TODO: Set ruby using expr.rubyVersion if not given.
+      gemPath = map (drv: "${drv}/${ruby.gemPath}") (
+        builtins.filter (value: lib.isDerivation value) (lib.attrValues gems)
+      );
+    };
+}