I could write a concrete example that will work in zig and fail in common lisp, but maybe this link is enough?

https://ziglang.org/#Order-independent-top-level-declaration...

Oh, so is the point that in Zig, functions with comptime parameters are more or less identical to regular functions in that regard?

Exactly. You can also use non-comptime functions in comptime, if it avoids certain types of stateful behaviour.

An example of this in the Zig math tests, where it tests calling the same function at both comptime and runtime: https://github.com/ziglang/zig/blob/33c4ad7f3a79aad5d7ea481a...

In common-lisp you could do something equivalent, but you'd have to wrap the definitions you want to be able at both compile and and run time in eval-when.