Microscheme: scheme for the Arduino | Hacker News Reader

Microscheme: scheme for the Arduino

microscheme.org

67 pointsducklord10 comments

Fun fact - "microscheme" means "integrated circuit" in Russian. Oddly fitting.

So far i don't like the fact it can't handle interrupts (unless by C code), and that it seem to ignore the C++ FFI completely.

That, and the fact that a garbage-collected language is to be run on a microcontroller - a device that is mostly used for realtime tasks. It won't be good for a quadcopter to go into a garbage collect subroutine during the control loop calculations.

Not a problem if you are aware of the issue, but how many people are?

Microscheme is not garbage collected, at least according to the documentation.

There's a form of faux-garbage-collection: you can wrap any form in `free!` and the heap pointer will be reset when that form finishes: http://microscheme.org/documentation#memman

This would be awful for general-purpose programming, but on a device with only 2.5kb of RAM to begin with you can usually pre-allocate anything that needs to survive that reset. I use this in my keyboard firmware's outer loop: http://atreus.technomancy.us/firmware2

>> "Microscheme has a robust FFI (Foreign Function Interface) meaning that C code may be invoked directly from (ms) programs. Therefore, the power of the existing wealth of Arduino libraries is available within Microscheme. "

Arduino is c++, and c++ FFI's are really hard. So how does this FFI work ?

According to a quick look through the documentation, C code is called though a simple interface: (call-c-func "c-function-name" args …). OTOH it didn't appear that it's possible to call Scheme from C, which may be a disadvantage in some cases.

You are right, no mention of C++. It's not clear how much of a problem that would be. IIRC wrapping C++ in "extern C" more or less enables C++ functions to be called from C. Don't know about compatibility of Arduino libraries, but possibly this is how Microscheme FFI works.

Is there python for Arduino? :)

Not AFAIK but you may be interested in https://micropython.org/

I would recommend the ESP8266, which is a much better microcontroller, with integrated wifi and a price tag of only $2. It runs Lua, C, Javascript and, most recently, MicroPython.

https://micropython.org

See http://arduino.stackexchange.com/questions/105/programming-a... for a (negative) answer.

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