That's true; on the ATMega32u4 it's the 2.5kb of RAM that kills you. The 16MHz clock speed is plenty fast for most microcontroller applications. That's why Micr

That's true; on the ATMega32u4 it's the 2.5kb of RAM that kills you. The 16MHz clock speed is plenty fast for most microcontroller applications. That's why Microscheme is just a subset of Scheme; there are no continuations or runtime eval in order to save memory. It's true that there are no structs, but it wouldn't be much of a stretch to add them. There's a discussion of writing a macroexpander in another Scheme runtime like Guile which can compile macros to microscheme output. (This is a bit like how ClojureScript lacks runtime eval but allows you to write compile-time macros in Clojure.) Writing a define-struct macro that compiles to vector-ref at runtime would be pretty trivial once you have a macroexpander working. https://github.com/ryansuchocki/microscheme/issues/8 If you're interested in hacking on a small Scheme implementation, I'd encourage you to give it a go. The author is very responsive and friendly.