Most built-in hooks in Jwno are normal hooks. They are used solely for their side effects, and their return values are ignored. The :window-created hook we saw above is a normal hook.
You can define and call a custom normal hook like this:
(:call-hook (in jwno/context :hook-manager) :world-dominated galaxy system planet)So here we have a custom hook called :world-dominated, and its registered functions should accept three arguments, galaxy, system and planet, pointing out the specific planet we just conquered.