From what I understand how Clojure works it creates a class with a method that has these fields. And as you didn't specify that your parameter is of a specific non-Object type (i.e. int) then it means that you pass only a reference. So whatever you pass you only copy the pointer. And I think it won't be optimized away. So if you care that your app won't have any duplicate pointers to things and it's already pricy for you then it has a cost for you. But if you aren't at that level of optimization then you shouldn't care about it.

yeah, i'm not really worried about it, just curious.

one more thing on the stack, but generally don't think there should be any cost beyond that

What about macros? What if I do a lot of macro expansions in real-time?

What does realtime mean?

Macro expansions will happen at compile time

Ah. I thought about the case when they also happen when I connect to a live app and actually ask it to run new code :thinking_face:

If you call eval you’re invoking the compiler

Ok. Then it means that I'll not have any problems if I'll connect via REPL because I'll already be using compiled chunks of code and only the top-level macro will be expanded by the compiler as deep as it needs to go.

The folks in the #C054XC5JVDZ channel are probably very interested in this...