LWN: Comments on "A tiny Python called Snek"

A tiny Python called Snek

zoobab — Wed, 05 Feb 2020 09:23:10 +0000

Any plan for STM32 boards? especially the popular and cheap STM32F103? They are ARM Cortex M3, so it should be close to the other ARM boards already supported...

A tiny Python called Snek

simcop2387 — Fri, 31 Jan 2020 20:35:16 +0000

It's not generally possible with the default ATMEGA328 processors on arduinos. Porting the code and everything generally works fine and is easy to do but the real problem is the lack of memory on them, only 2KB of RAM. That causes a number of problems for LUA to do anything non-trivial due to the way the VM and everything works. That said I use a cortex m3 + lua to run my christmas lights. You don't need much more ram for it to suddenly be useful, about 4K seems to be the spot in my experience, and the 32kb on the arm processor I use is obviously morebetter.

A tiny Python called Snek

ejr — Thu, 30 Jan 2020 22:34:03 +0000

If you use signaling NaNs for other types, you can run through a sequence of arithmetic operations and check if they were actually numbers after the fact. Old technique.

A tiny Python called Snek

Wol — Thu, 30 Jan 2020 11:30:28 +0000

Could something like this help... ?

https://www.amazon.co.uk/Serial-Adapter-Prolific-Chipset-...

or this?

https://www.perle.com/products/multiport-serial-card.shtm...

Cheers,
Wol

A tiny Python called Snek

keithp — Fri, 24 Jan 2020 18:36:00 +0000

Sure! I've already used the esp8266 toolchain packaged in Debian as I tested the Picolibc port done by Jonathan McDowell.

A tiny Python called Snek

SEJeff — Fri, 24 Jan 2020 14:38:31 +0000

If a little hardware fairy were to gift you an adafruit huzzah esp8266, would you consider porting to it?

A tiny Python called Snek

keithp — Fri, 24 Jan 2020 06:06:59 +0000

There's lots of potentially interesting languages to teach new programmers, but our program focuses on building robots (with Lego components!), which means having hardware to connect the computer with motors and sensors. Finding hardware that can do that turns out to be non-trivial.

When the old Macintosh machines stop working, the interface hardware will no longer have anything to connect to. Those use a proprietary serial protocol hooked up to the original Macintosh serial ports. Maybe those interfaces could be connected to a modern machine?

For Snek, I had hoped to use existing Arduino-compatible hardware, but couldn't find any integrated boards capable of driving 9V motors and servos. So I ended up building my own, which has resulted in a Crowd Supply campaign... Somehow this feels a lot like yak shaving.

A tiny Python called Snek

keithp — Fri, 24 Jan 2020 05:56:26 +0000

Yeah, the ESP32 isn't exactly tiny. But, it's something I had lying around, so naturally I ported Snek to it. Somehow, I tend to collect tiny microcontroller boards. They're like coat hangers around here.

MicroPython uses a couple hundred kB of ROM; which is amazingly small considering how much Python that includes. Snek is a much less capable language, but it can squeeze down to about 32kB of ROM if you leave out the math functions.

Snek currently has ports for:

Adafruit Crickit FeatherWing (Atmel SAMD21)
Arduino Duemilanove (Atmel ATmega 328P)
ESP32
Adafruit Feather M0 Express (Atmel SAMD32)
SiFive HiFive1 Revb (RISC-V)
Adafruit ItsyBitsy (Atmel ATmega 32u4)
Arduino Mega (Atmel ATmega 2560)
Adafruit Metro M0 (Atmel SAMD21)
Arduino Nano 33 IoT (Atmel SAMD21)
Adafruit Circuit Playground Express (Atmel SAMD21)
POSIX (for testing and debugging)
QEMU for ARM (Cortex M3)
QEMU for RISC-V (rv32imac)
Arduino µduino from Crowd Supply (Atmel ATmega 32u4)

These range from 32kB of ROM and 2kB of RAM all the way up to several hundred kB of ROM and a bunch of RAM.

Lost his magic Smoke...

rahvin — Fri, 24 Jan 2020 00:58:20 +0000

Even with the wonders of modern tech and the durability of old tech, Magic Smoke strikes again! I've heard those old Apple II's have a pretty limited amount of magic smoke.

A tiny Python called Snek

SEJeff — Thu, 23 Jan 2020 22:58:49 +0000

I find it interesting that this is supposed to be smaller than micropython and works on the esp32, but not the smaller esp8266, which micropython works on.

A tiny Python called Snek

ceplm — Thu, 23 Jan 2020 21:13:46 +0000

> When the OS 9 Macs needed to run Logo are no longer available, we'll need to find something new...

What’s wrong with UCB Logo? https://en.wikipedia.org/wiki/Logo_(programming_language)

A tiny Python called Snek

keithp — Thu, 23 Jan 2020 20:53:43 +0000

The main goal of the Snek project was to build a small, easy to teach language that would be useful later on. To me, that meant doing something based on Python.

My daughter took an introductory programming class as part of her geology degree. The class used Python, but most of the time was spent learning things also in Snek. Most of the examples and classwork would run (unchanged) using Snek instead of Python.

A tiny Lua for Arduino-scale machines could be a fun project though. Our robotics program teaches students three languages (Snek, Logo and ROBOLAB) and lets them choose which language to use for further work. When the OS 9 Macs needed to run Logo are no longer available, we'll need to find something new...

A tiny Python called Snek

dgm — Thu, 23 Jan 2020 12:10:09 +0000

I'm not sure if Lua (or eLua) could be made to run on the target platform without reimplementing the interpreter.

A tiny Python called Snek

ceplm — Thu, 23 Jan 2020 11:20:48 +0000

Hasn’t he just reinvented Lua? I mean for the small embedded hardware, that should be it, shoudln't it?

A tiny Python called Snek

keithp — Wed, 22 Jan 2020 22:59:33 +0000

Thanks for the explanation; I was unaware of the call to serialEventRun. Useful bits!

From a teaching perspective, I did have to explain the overall structure (setup called once, loop called again and again), but your comment about avoiding the need to teach for(;;) or while(1) resonates with my experience. It's faster to explain in words what the system does than get students to type the loop syntax in by hand.

A tiny Python called Snek

Cyberax — Wed, 22 Jan 2020 22:08:28 +0000

It also saves a level of indentation, making code a bit more readable.

A tiny Python called Snek

vadim — Wed, 22 Jan 2020 21:49:01 +0000

Finding out why Arduino uses two functions (setup() and loop()) is easy, just look in the code. You'll find this in main:

    setup();

    for (;;) {
        loop();
        if (serialEventRun) serialEventRun();
    }

So, I take it that this situation has 4 reasons for existing:

It saves the need to know how to make a loop. This is useful because near any Arduino program will need to loop, so that's one thing less to figure out before getting something that works.
It avoids the rather obtuse syntaxes of "for(;;)" or "while(1)", which a new student won't yet understand, and would need additional explanation.
It avoids the need for the user to call serialEventRun(), which is even more obscure to newbies, not to speak of the 'if' bit.
It allows for more processing behind the scenes to be inserted if needed, without requiring existing code to be modified.

So I would say on the balance it's a good thing. It allows getting down to business as quickly as possible, and does its best to avoid the student having to write arcane incantations that they don't understand the purpose of, and which they could screw up.