You can do that in most (all?) Scheme implementations. Macros are powerful, yo. This goes back to another discussion here: just because you've implemented a la

You can do that in most (all?) Scheme implementations. Macros are powerful, yo. This goes back to another discussion here: just because you've implemented a language doesn't mean you've implemented it well. Sure, I can implement all the syntax of what I want. But is it fast? Does it report errors well? Am I enforcing my type system, or can I accidentally drop back into normal Scheme? I think a lot of times new Lispers learn macros and, drunk with their newfound power, start writing 20% implementations that get them 80% to mature languages. And if you don't need or want the other 20% of a mature language, then that's fine. But if you do need or want the other 20% of a mature language, then you'll quickly discover that the Pareto Principle[1] applies. Lisp metaprogramming can be super powerful, but it's not a magic bullet: not only does it not kill werewolves but you can shoot yourself in the foot with it. [1] https://en.wikipedia.org/wiki/Pareto_principle#In_computing https://en.wikipedia.org/wiki/Pareto_principle#In_computing