Ah, yes, I should have been more precise. It doesn't have an equivalent of an interface/trait/protocol with dynamic dispatch.

Yes, you can pass around an object of procedures, but that is awkward, doesn't have any support from the language or stdlib, and from what I can tell isn't a normal thing that is done.

Even back in 2013 there were these ideas: https://forum.nim-lang.org/t/278

I think you & I are really back & forth-ing "the PLang not enforcing/strongly encouraging a very specific way of doing things that a whole ecosystem/community organizes around". Relying instead on self-organization has many pros & cons, to be sure. Lisp suffered much the same "until" Common Lisp (which still leaves many things open). My tag line lately is: delegation affords so much, but trust sure is tricky. Much of the time people seem to discount the often rather large cost of establishing/maintaining trust. (I'm not saying you are - just that it's an easy thing to do. I think it's why there is this is a big megathread on "trusting rust", even though "rust" is a veritable suffix of "trust". Lol.)