I thought they just had special rules for expressions with a car in {set!, lambda, if, quote, ...} such that arguments to those are not evaluated. From there yo

I thought they just had special rules for expressions with a car in {set!, lambda, if, quote, ...} such that arguments to those are not evaluated. From there you can construct whatever else. I might be mistaken, I'm not clear on the history of it. You know what you might like, if you haven't seen it yet, is the Kernel programming language, a Scheme where everything, including macros, is first-class.