How can I call an external command from within Miller (mlr)’s DSL?

Suppose I have the following CSV:

$ cat test.csv
id,domain
1,foo.com
2,bar.com

Using mlr put, I can easily map any function over a field in the CSV, as long as I can define it in the Miller DSL . So, for example, mlr --csv put '$id = $id + 1' will increment the id by 1 for each record. But what if I can’t define the function in Miller’s DSL, perhaps because it is not pure? Suppose I wanted to map each domain in the CSV to an IP address. I’d like to do something like mlr --csv put '$ip = shell("nslookup $domain"). Is there an easy way to do this? Currently I am extracting the input field into a separate file, rewriting it in a separate shell script, and adding the result back in with mlr join. However, this is pretty messy, because my CSV is full of quoted commas and newlines, which I need to carefully handle myself rather than relying on Miller.