This definitely rings true to me. We give an interview that’s basically a simple parser, and ask candidates to do it recursively(in Elixir) using function head

This definitely rings true to me. We give an interview that’s basically a simple parser, and ask candidates to do it recursively(in Elixir) using function head instead of Enumerable. We link to the relevant docs and it’s a paired exercise with tests built in. It’s generally been a good predictor of candidates ability to work in our code base and collaborate. The whole thing can be done in 50loc and is not meant to be terribly hard.