- Hoot is a whole-program compiler so compilation times are longer than in separate compilation because there's simply a lot more code to deal with. However, it's possible to compile multiple separate modules and have them work together. One module would serve as the primary module that exports its ABI and the other modules would be secondary modules that import their ABI. I recently did this for a program by splitting up the backend (which was a lot of code that rarely changed) and the frontend (which was much smaller and quicker to compile). The --mode=secondary flag for guild compile-wasm is what you should look into. In JS, you'd call load_main for the main module and then load_extension for each secondary module. See here for an example.
- Correct, Geiser is not supported right now so there isn't really a usable workflow for live hacking.. We have plans for a geiser-hoot.el package but we haven't gotten to it yet. Since the REPL would be running inside a web browser tab, it cannot act as a REPL server like we need it to. Resolving this will require introducing a WebSocket daemon middleman, much like Fennel's webrepl. I hope this is something I can work on soon.
- Yes, I would like to catch that unbound top-level error and print a better message rather than just a raw backtrace. That error is generated from an early phase in the compiler defined in the (hoot library-group) module. I filed an issue to track it.