hedgehog

Try Hedgehog: https://github.com/sbp/hedgehog

https://en.wikipedia.org/wiki/SIOD is lighter weight than almost anything. Way smaller than Lua. Also look at Hedgehog Lisp. The bytecode compiler (runs on a PC) is separate from the interpreter, i.e. there is no REPL. But it means that the interpreter is only about 20KB of code. It's quite practical. It's not Scheme but rather is a functional Lisp (immutable data including AVL trees as the main lookup structure) and it is tail recursive. https://github.com/sbp/hedgehog

That is cool, it looks like Python, how did they get it so small? Is it garbage collected? Is the interpreter entirely resident in the Arduino or does it rely on an external communication app hosting the compiler? That approach is actually underutilized in my opinion. I gotta say that AVR Arduino hardware is almost silly by now. The Raspberry Pi Pico is probably the successor basic MCU board these days. It costs $4 retail, and has a dual ARM M0+ cpu with 264KB of ram and 2MB of SPI flash, so it can run Micropython and other relatively full featured software. Also check out my old favorite Hedgehog Lisp: https://github.com/sbp/hedgehog It's a functional-style Lisp dialect whose VM is 20K bytes. It uses an external ahead-of-time compiler, no resident interpreter.

Ulisp is cute but (when I looked at it a while back) way too limited and inefficient. My favourite Lisp of this type is Hedgehog, which should run very nicely on a Pi Pico. Its main drawback is it has no REPL, but instead uses a separate byte-compiler that for some reason is written in C. https://github.com/sbp/hedgehog

The rib encoding looks very clever. I need to digest the full implications of that. > 4KB is impressively tiny, but any machine where 4k vs 20k makes a big difference is unlikely to have enough ram to run garbage collected applications. Yeah, the paper itself says that the heap was 240K. A 4K system isn't very helpful if your heap is 240K. I'd like to see how this runs (if at all) with a 4K heap. Deceptively straightforward things like map and apply can cons up a whopping amount of intermediate garbage. > I would like to have seen Hedgehog Lisp ( https://github.com/sbp/hedgehog ) in the comparison chart, since it has actually been used for practical projects Links to projects?

Paper is acm-walled but code repo is https://github.com/udem-dlteam/ribbit . I would like to have seen Hedgehog Lisp ( https://github.com/sbp/hedgehog ) in the comparison chart, since it has actually been used for practical projects. Its VM is around 20KB of object code. 4KB is impressively tiny, but any machine where 4k vs 20k makes a big difference is unlikely to have enough ram to run garbage collected applications. That seems to call more something more like Forth rather than Scheme. Hedgehog is a somewhat weird functional dialect of Lisp and I've been wanting for a while to convert it to a Scheme subset (mostly just using Scheme syntax instead of defun, etc) so people would be more familiar with it. Added: paper is here http://www.iro.umontreal.ca/~feeley/papers/YvonFeeleyVMIL21....