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How can you evaluate a complex macro at compile-time if you are doing AoT compilation? Lisp macros are not like C macros where simple substitution would suffice

How can you evaluate a complex macro at compile-time if you are doing AoT compilation? Lisp macros are not like C macros where simple substitution would suffice, they need to be evaluated. I found my exact question on stackoverflow: https://stackoverflow.com/questions/7072980/how-do-you-compile-macros-in-a-lisp-compiler https://stackoverflow.com/questions/7072980/how-do-you-compi... The answers on SO are still not clear to me, some people say the macros can be evaluated at compile time, some say that the runtime needs to include some kind of interpreted to run macros. Some say incremental compilation is key to understand how macros get evaluated at compile time. I will run experiments on this.

erik_seaberg 4y ago
A compiled Lisp program might not be able to eval a list or load a source file, for the same reason a packaged jar generally won’t contain a copy of the Java compiler. I think eval-when controls which macro definitions (if any) need to be available at runtime, rather than being expanded away while compiling functions.
- terminalcommand 4y ago
  From my conversation with lispm above, I discovered that each binary SBCL produces includes the compiler as well. This is what is meant by incremental compilation I get it. When I first heard the term incremental compilation, I thought of a process like going through the ast couple of times and evaluating expressions. This wasn't what it meant. Now it makes sense. You include the lisp compiler in each binary. For parts you cannot evaluate at compile time, you compile at runtime, just like a JIT.