Idea: fully native code

I've actually been wondering about this - effectively exposing an Arduino environment that runs on top of Espruino (maybe even using the Arduino IDE). The idea being initially to get more folks writing Bangle.js apps.

However there are a few issues:

• I can't expose all the nrf* API calls - their location changes every time a firmware is compiled, and the only simple way around that is to have a table of their locations. I can't afford to have a massive table of the 100s of nrf calls sitting in flash on every device - and sometimes calls aren't even there (they aren't compiled in, or are inlined).
  
• As you note with NFC, you're seeing a delay executing because of the event loop. I can't disable that event loop because that's basically what Espruino is, so even though you could write your code in C, you might still see a bit of a delay between calling of loop.
  
  

I think the delay between calls to loop is to be expected in many devices (regardless of Espruino). If you need time critical you really need to write code that runs in interrupts. In your case (and I think I mentioned this before when you were asking about NFC) I think you really just need to make the changes inside the Espruino firmware in the interrupt handler.

It's actually pretty easy to compile Espruino, and you get access to all the nrf functions, plus you'll definitely be able to service the NFC command quickly regardless of what else is going on.

So I think having the ability to write native code would be really cool, and I'm interested in doing it - but I think in your case with NFC it probably wouldn't help you anyway