@josevalim I gave it more thought and realized that I can move group_maybe to wadler.ex but instead of getting opts and extracting opts[:depth] I can simply and move the duty of looking up current depth to inspect implementations. That way a call to group_maybe will look like

```Elixir
# in inspect implementation
opts = inc_depth(opts)
# ...
group_maybe(
  concat(
    # ...
  ),
  opts[:depth]
)
```

If you're OK with that, that's what I'll do.