I have a hard time trusting the CL macros I write because of unexpected interactions with the context that I use them in. While it is the case that CL macros are more powerful than the R6RS macros-by-example system, Racket’s system (and some other newer languages that have adopted things pioneered by Scheme and Racket, such as Elixir) give you hygienic macros without sacrificing expressive power.
I want my macros to be easy to write correctly. That can only happen when the system has proper hygiene.
Table saws were only improved by the addition of an emergency stop to prevent people from maiming themselves. Power tools don’t have to be dangerous.
If you are wanting to introduce variable capture you better be really explicit about when you want it.
If there’s no hygiene, I have to know everything about how the macro is implemented in order to trust it and use it confidently. Might be fine for small shorthand, but that won’t scale. You need non-leaky abstractions to build on them.
Racket’s `syntax-parse` and “syntax parameters” show that you can have it both ways: procedural macros that are hygienic by default, but with an explicit escape hatch when you do want to introduce new bindings into the macro call site. It also gives you much much better errors.
CL macros are about as dangerous as malloc/free, but without years of experience and tools like Valgrind to debug. They’re hard to trust and get right.
Racket macros are like GC/affine typing: everything is correct by construction.
I've used table saws, with and without protection. They're all dangerous as fck, because removing the chance of getting hurt means converting it to a completely different kind of tool. Chain saws, same thing. Power tools.
Of course we want them to be as safe as possible, but that's a different discussion. All attempts I've seen so far have dropped functionality to get there.
> All attempts I've seen so far have dropped functionality to get there.
Well, then I recommend you take a look at Racket's macro system: Racket gives you hygienic macros without any loss of power. (It's actually more powerful and expressive than CL macros.)
I want my macros to be easy to write correctly. That can only happen when the system has proper hygiene.