> Everyone jumped on it, as production lisps don't implement macros this way. But it's the natural way to implement them in a SICP style metacircular evaluator,

> Everyone jumped on it, as production lisps don't implement macros this way. But it's the natural way to implement them in a SICP style metacircular evaluator, and a good way to learn them. I don't think it is overly useful to explain people how to extend a SICP style metacircular evaluator with some custom macro system. It's often a part of the Lisp journey, but not something I would recommend for basic Lisp teaching. If I want people to program in Lisp, I give them a real Lisp and teach them how to program with it. > This is about mental models Sure, but you are teaching them the wrong mental models (macros tied to an evaluator), while I would focus on the model of general code transformations and the tools to make effective use of them. > And in my opinion this thread is full of experts who have forgotten what it's like to not understand how macros work. Not sure who you talk about, but I have been explaining macros to people already in the 80s.