No idea about mruby/C or picoruby but MicroPython is very popular, enough that I'd just settle on it for devices can handle it. It runs nicely in 256k of flash and 32k of ram, on the small adafruit trinket devices. It was shoehorned into the v1 BBC microbit which had 256k of flash and just 16k of ram, but that was apparently painful.<p>Smaller include Lua and maybe Hedgehog Lisp. Below that there is ulisp but that is sort of a toy. Also there is Javacard and J2ME depending on device size.<p>Below that you're probably best off forgoing garbage collection and using Forth or a cross compiled language.
Will have to look closer at picoruby. I do love MicroPython development. One support thing is how easy it is to combine with C, because to get the most out of microcontroller devices one really needs to use low-level languages from time to time.
I'm the developer of Juniper, a functional reactive programming language for the Arduino. It's very possible to run high level code on small devices. This even includes things like closures, which Juniper allocates on the stack!<p><a href="https://www.juniper-lang.org/" rel="nofollow">https://www.juniper-lang.org/</a>
picoruby is a lot of fun. It's a reimplementation of mruby/c which is even smaller. You might be interested in my friend and creator HASUMI Hitoshi's presentation. He shows off his Ruby REPL that runs on the Raspberry Pi pico.
Recently he ported picoruby to other microcontrollers.<p><a href="https://youtu.be/WxZNE5zTAjg?si=7DQUcQg80RMZoU0b" rel="nofollow">https://youtu.be/WxZNE5zTAjg?si=7DQUcQg80RMZoU0b</a>
You can look at the documentation on their web site too: <a href="https://picoruby.github.io" rel="nofollow">https://picoruby.github.io</a>
If this kind of stuff interests you, you may also like micropython[1], which is currently overwhelmingly dominate in this niche.<p>1: <a href="https://github.com/micropython/micropython" rel="nofollow">https://github.com/micropython/micropython</a>
256KB ROM/128KB RAM isn't very small.<p>That is larger than the average computer through about 1990 ...<p>(I know people will say I'm being pedantic. However, RAM and Flash define most of the price of a microcontroller. So, a factor of two--especially in RAM--means a significantly smaller and cheaper chip.)
some people hate to use C. Some people embrace it, even love it (including many game devs!). You have full control! But i wonder, what do HN folks think about these pico implementations of ruby, a complex language made for the tiniest devices, such as sensors? I mean.. is C really that bad??<p>also, it's very cool they're still being maintained!