stamourv

picobit

C2015–2025

stamourv / picobit

picobit

A Compact Scheme System for Microcontrollers

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13Mentions

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188GitHub stars

REPOSITORY AT A GLANCE

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What it is

A Compact Scheme System for Microcontrollers

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Where it is used

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This week on Hacker News

Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 3:56:07 PM UTC.

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Mentions over time

HN mentions by year13 dated mentions

Observed mentions: 2015-01-06 19:53:47 UTC to 2025-11-23 18:25:14 UTC.

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

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Period	Start (UTC)	End (exclusive, UTC)	Mentions	Comments
2015	2015-01-01 00:00:00 UTC	2016-01-01 00:00:00 UTC	6	6
2016	2016-01-01 00:00:00 UTC	2017-01-01 00:00:00 UTC	1	1
2017	2017-01-01 00:00:00 UTC	2018-01-01 00:00:00 UTC	1	1
2018	2018-01-01 00:00:00 UTC	2019-01-01 00:00:00 UTC	2	2
2019	2019-01-01 00:00:00 UTC	2020-01-01 00:00:00 UTC	1	1
2020	2020-01-01 00:00:00 UTC	2021-01-01 00:00:00 UTC	0	0
2021	2021-01-01 00:00:00 UTC	2022-01-01 00:00:00 UTC	0	0
2022	2022-01-01 00:00:00 UTC	2023-01-01 00:00:00 UTC	1	1
2023	2023-01-01 00:00:00 UTC	2024-01-01 00:00:00 UTC	0	0
2024	2024-01-01 00:00:00 UTC	2025-01-01 00:00:00 UTC	0	0
2025	2025-01-01 00:00:00 UTC	2026-01-01 00:00:00 UTC	1	1

What Hacker News says

13 sources

attila-lendvai·Nov 23, 2025

that's an often repeated misconception about lisps. lisps are pretty good at low-level programming, but then you'll need to make some compromises like abandoning the reliance on the GC and managing memory manually (which is still a lot easier than in other languages due to the metaprogramming capabilities). there are lisps that can compile themselves to machine code in 2-4000 LoC altogether (i.e. compiler and assembler included; https://github.com/attila-lendvai/maru). i'm not saying that there are lisp-based solutions that are ready for use in the industry. what i'm saying is that the lisp langauge is not at all an obstacle for memory-limited and/or real-time programs. it's just that few people use them, especially in those fields. e.g. i'd easily prefer a lisp to put together a specialized byte-code interpreter to shrink firmware size f

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or small embedded devices (e.g. for a radio https://github.com/armel/uv-k5-firmware-custom/discussions/4...). and there are interesting experiments for direct compilation, too: BIT: A Very Compact #Scheme System for #Microcontrollers (#lisp #embedded) http://www.iro.umontreal.ca/~feeley/papers/DubeFeeleyHOSC05.... "We demonstrate that with this system it is clearly possible to run realistic Scheme programs on a microcontroller with as little as 3 to 4 KB of RAM. Programs that access the whole Scheme library require only 13 KB of ROM." "Many of the techniques [...] are part of the Scheme and Lisp implementation folklore. [...] We cite relevant previous work for the less well known implementation techniques." BIT inspired PICOBIT (last changed in 2015): https://github.com/stamourv/picobit racket (only a .so into an already running VM): http://download.racket-lang.org/docs/5.1.3/html/raco/ext.htm... scheme: gambit, chicken

In Racket v9.0

alexisread·May 19, 2022

I think it depends on how hard-core you want to go. Fennel runs in 2K of ram https://news.ycombinator.com/item?id=31029478 Picbit ran in 256bytes, it's descendent is slightly larger https://github.com/stamourv/picobit Staapl compiles scheme to Forth, to also run on the PIC18 https://www.concatenative.org/wiki/view/Staapl Of course there is also Sectorlisp, the smallest language out there in 436bytes, 64k ram https://justine.lol/sectorlisp2/

In Pikascript: An ultra-lightweight Python engine that can run in 4Kb of RAM

DonHopkins·May 27, 2019

Also from David A. Wheeler's 6502 Language Implementation Approaches (archive.org-ified to the time the links were written, or best approximation): https://web.archive.org/web/20181112182918/https://dwheeler.... Lisp/LOGO The "skimp" page also includes a list of several 8-bit LISP implementations, including several for the 6502 [1]. This discussion lists more [2]. One useful implementation discussion (of many!) is R. Kent Dybvig's "Three Implementation Models for Scheme". University of North Carolina Computer Science Technical Report 87-011 [Ph.D. Dissertation], April 1987 [3]. neslisp [4] is a small subset of Lisp that generates 6502 code (NES); the as of version 0.1 it is released under the GPLv2 license (and thus is open source software). An older version is available via neslisp on Google code [5]. Picobit [6] (GPLv3) looks interestin

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g. You program in Lisp (specifically a variant of Scheme) on a larger system; it then compiles to a VM that runs on the target. Currently it does not support the 6502, but the system is designed to be portable and it looks to me that it'd be relatively easy to port to a 6502. Lysp [7] (MIT license) is another small implementation of Lisp. It doesn't directly support 6502 and is in C, but it's small... so it might not be hard to transliterate. A related program from the same developer is Maru [8], which can self-host. This could be a reasonable starting point for creating a 6502 Lisp. Turning the Apple //e into a lisp machine, part 1 [9] refers to this Lisp interpreter for the Apple //e [10] (MIT license). They also show a clever bootstrap approach: they send code via the audio jack (!). There's more that can be done; Lisp was originally developed in 1965, on even smaller systems. The book "Lisp in Small Pieces", Program Transformation in Lisp [11], this Scheme page [12] and these details on implementation [13] are all of interest. R. Kent Dybvig's "Three Implementation Models for Scheme" [14] shows how to implement Scheme while still keeping most stuff on the stack. Tagging could be difficult, but an alternative (that I believe was done for early Lisp implementations) is to partition the memory into regions; to determine the tag, just check which memory region it is in. It might be possible to start with PicoLisp [15] to create a 6502 version. There is a trivial ACL2 implementation of Lisp (GPL) [16] that I converted into Common Lisp ( compiler [17], run-time [18]; See Wolfgang Goerigk's "Compiler Verification Revisited" [19] for more). I know that there was an "InterLISP 65" available for Atari's 6502-based line. Various full LOGO implementations were available as well. [1] skimp: http://web.archive.org/web/20100131151915/http://www.ip9.org... [2] discussion: [missing] [3] Three Implementation Models for Scheme: https://web.archive.org/web/20160817185323/http://www.cs.ind... [4] neslisp: https://web.archive.org/web/20160319025751/http://gomez.yell... sources: https://web.archive.org/web/20160619185108/http://gomez.yell... [5] google code nelisp: [missing] [6] Picobit: https://web.archive.org/web/20150106110223/https://github.co... current: https://github.com/stamourv/picobit [7] Lysp: https://web.archive.org/web/20180929064442/http://piumarta.c... source: browse: https://web.archive.org/web/20170507045957/http://www.piumar... download: https://web.archive.org/web/20180929064442/http://piumarta.c... [8] Maru: https://web.archive.org/web/20181206222700/http://piumarta.c... source: browse: https://web.archive.org/web/20181206222700/http://piumarta.c... download: https://web.archive.org/web/20181206222700/http://piumarta.c... [9] Turning the Apple //e into a lisp machine, part 1: https://web.archive.org/web/20190109003417/http://blog.nulls... [10] google code turtles: https://web.archive.org/web/20180611002847/https://github.co... current: https://github.com/hausdorff/turtles [11] Program Transformation in Lisp: http://www.findinglisp.com/blog/2004/06/program-transformati... [12] this Scheme page: [missing] [13] these details on implementation: https://web.archive.org/web/20180801195133/http://library.re... [14] Three Implementation Models for Scheme: https://web.archive.org/web/20190503102138/https://cs.indian... [15] PicoLisp: https://web.archive.org/web/20181124064229/http://www.softwa... [16] ACL2 implementation of Lisp (GPL): https://web.archive.org/web/20090217043459/http://www.cs.ute... [17] compiler: https://web.archive.org/web/20160320015734/http://www.dwheel... [18] runtime: [missing] [19] Compiler Verification Revisited: [missing] citation: https://dl.acm.org/citation.cfm?id=369101 buy chapter: https://link.springer.com/chapter/10.1007/978-1-4757-3188-0_...

In MakerLisp: Embedded Lisp Machine

snaky·Nov 28, 2018

To add to the list, PicoBit Scheme for microcontrollers, currently PIC18 and ARM, https://github.com/stamourv/picobit There was a port of one of PicoBit predecessors, Bit Scheme, to the XMOS architecture, with realtime GC and support for the native XMOS features http://soft.vub.ac.be/~cderoove/publications/master_thesis_r...

In Perchance to Scheme (2016)

pflanze·Oct 18, 2018

The PIC18 can run the following Scheme implementation: https://github.com/stamourv/picobit (The (last of the original) main author(s) has stopped maintaining it, although there are many forks, some of which might be maintained, I haven't checked.)

In Haskell's kind system: a primer

xfer·Oct 3, 2017

Close to the hardware can also be done with scheme and indeed has been done in the past. Look at all the smartcards, running a JVM. For scheme, it just requires some engineering effort and there is not much demand for it. Btw, there is picobit(https://github.com/stamourv/picobit) which can be run on micro-controllers.

In Gerbil – An opinionated dialect of Scheme designed for systems programming

bsder·Dec 7, 2016

I wish people would quit promulgating Forth. Sorry, but it is not a production language. It is a puzzle language. Many things which are straightforward in even the worst programming language are a brain teaser to figure out how to organize in the "Forth Way(tm)". Scheme and Lua come closest to my ideal. However, I just can't deal with 1-based indexing from Lua. Sorry. Too many things talk to C API's. Scheme is okay, but almost none of them are truly small anymore. Even the ones like picobit (https://github.com/stamourv/picobit) require quite some grunty support from a desktop machine outside the processor.

In GRiSP – Erlang-based IoT hardware platform

bsder·Jul 27, 2015

Don't forget Picobit which is Scheme: https://github.com/stamourv/picobit

In JerryScript – A JavaScript Engine for Internet of Things

bsder·Jul 27, 2015

> Ardunino Uno (ATmega CPU): 2KB RAM, 32KB ROM - Too small. To be fair, that system really doesn't run anything dynamic well. However, your point stands. Requiring 64K of RAM puts this above most ARM Cortex M0 chips. Picobit (https://github.com/stamourv/picobit) sits comfortably in 16K ROM/4K RAM. There's no good reason why Javascript vouldn't do the same.

In JerryScript – A JavaScript Engine for Internet of Things

jarcane·Jun 20, 2015

There's several Scheme implementations now built for microcontroller/embedded use, Picobit for example: https://github.com/stamourv/picobit

In PilOS – A Stand-Alone Operating System

_sh·Jun 20, 2015

Also picobit for scheme goodness: https://github.com/stamourv/picobit Doesn't support full numeric tower (no floats), but does implement 'unbound precision integers'. See §5.1 of this paper: http://www.iro.umontreal.ca/~feeley/papers/StAmourFeeleyIFL0...

In PilOS – A Stand-Alone Operating System

Kototama·Jun 11, 2015

If you are interested in this, check also PicoBit: https://github.com/stamourv/picobit

In Reviving Lisp for smaller programmable machines

pkhuong·Jan 6, 2015

Looks like PICBIT is finally open source: https://github.com/stamourv/picobit We use(d?) it at U of Montreal to drive small PIC18 robots. Except for the one time I had to debug its GC, it was a fine platform, even for HS students.

In Using Microscheme to write a keyboard controller, part 1