[ICWiener]

Macros do not necessarly transform code at compile-time. A late-binding interpretation is possible. See for example http://programmers.stackexchange.com/a/274200/33157.

[wtetzner]

Even in an interpreter, they're expanded at "Load Time" as opposed to runtime.

[ICWiener]

I am not sure, but it seems that this may be implementation-dependent.