Duktape VS MicroPython

Im my projects I search for single file libs.(like https://github.com/svaarala/duktape etc...)

Use lrand48(), or better, implement a high-quality RNG like PCG or splitmix64.

You can also refer to the Unicode routines of other small JS engines[1,2], those don’t use ICU either, although the implementations are mercilessly size-optimized (to put it politely) and restricted to what the target JS version requires (e.g. casemapping but no normalization).

[1] https://github.com/bellard/quickjs/blob/master/libunicode.c

[2] https://github.com/svaarala/duktape/blob/master/src-input/du...

> memcpy from bytes to a NaN should work fine

Signaling NaNs are explicitly undefined in C11 F.2.1.: "This specification does not define the behavior of signaling NaNs." - and in practice may be "quieted" by conversion to Quiet NaNs, changing their bit patterns. Fast math optimization flags will also break the hell out of your code by assuming NaNs are impossible. I want to say there are more circumstances where optimizers and compiler generated code can butcher your NaN payloads, but I'd be working off recollected hearsay and I can't find a source, so don't quote me on that.

NaN boxing is common enough that, if you take the right precautions, a modern compiler should probably support it, maybe. NaN boxing is uncommon enough that, if your codebase needs to be sufficiently portable, you need an opt out for when it breaks. Let's review duktape's scars:

https://github.com/svaarala/duktape/blob/123d9426d5e5b36d5da...

https://github.com/svaarala/duktape/blob/5252b7a50611a3cb8bf...

https://github.com/svaarala/duktape/blob/224a0b89ca08a36e37e...

Note that "the right precautions" involve unions and proper integer types to avoid optimizer-invoked rewrites of the value and debugging when things go wrong, not simply YOLOing bytes into a double via memcpy. Note that debugging when it all goes terribly wrong can be quite painful. I've personally had the misfortune of being forced to debug duktape being built with fast math optimizatoins enabled on one "rare" platform + build configuration that wasn't caught by duktape's #if defined(__FAST_MATH__) checks linked above (wasn't Clang nor GCC, so go figure it didn't make the same #define)

I was expecting this to be about Duktape <https://github.com/svaarala/duktape>, but heh, for sure no. I'd bet $1 there's no way youtube-dl would switch, but I wonder if yt-dlp would?

Fast math optimizations can break code like this by breaking isNaN.

I was porting a C++ project to a certain platform - and that platform enabled a -ffast-math equivalent by default in Release (but not Debug) builds! This broke duktape, a JS engine said project embedded, in some nasty and subtle ways. Instead of storing a number/pointer/??? (8 bytes) + type tag (4? bytes) for each dynamically typed JS value, duktape can bit-pack values into a single 8 byte "double" value by storing object/string handles as NaN values - this isn't an uncommon trick for dynamically typed scripting stuff:

https://github.com/svaarala/duktape/blob/c3722054ea4a4e50f48...

Naturally, the -ffast-math equivalent broke isNaN checks, which caused random object/string handles to be mistakenly reinterpreted as "numbers" - but only in Release builds, for this one particular platform, in one rarely taken branch, so neither QA nor CI caught it, leading to hours of manufacturing a repro case, stepping through an absurd amount of code, and then finally looking at the default build rules and facepalming.

Cursing the platform vendor under my breath, I overrode the defaults to align with the defaults of every other config x platform combination we already had: no fast math. If you want those optimizations, use SSE-friendly NaN-avoiding intrinsics - or, if you must use the compiler flags, ensure you do so consistently across build configs and platforms, perhaps limited to a few TUs or modules if possible. This allows you to have a chance at using your Debug builds to debug the resulting "optimizations".

Sure. For example, DukTape is an implementation of Javascript designed to be embedded in other projects. Google's V8 Javascript engine (used in Chrome), can also be embedded, see Node.Js for example.

- Duktape (4.8k stars)

Just putting my hand up to say that MicroPython is awesome (and runs on the RP2040). https://micropython.org

Gah, I just ordered one on impulse [1]. I've wanted to build out a WiFi PDA for quite some time now and I like this hardware.

I'm quite liking the idea of running tulip MicroPython [2] on it, or going back to pure MicroPython [3] and writing some drivers. Apparently something like ampy can be used to upload/download Python files [4].

Threads could be quite exciting for running multiple programs at once [5], although I have no idea what it means for two programs to fight over GPIO! It does seem as though MicroPython can only utilise a single core [6].

[1] https://www.lilygo.cc/products/t-deck?variant=43087936487605

[2] https://github.com/bwhitman/tulipcc/tree/main/tulip/tdeck

[3] https://docs.micropython.org/en/latest/esp32/tutorial/intro....

[4] https://www.digikey.co.uk/en/maker/projects/micropython-basi...

[5] https://docs.micropython.org/en/latest/library/_thread.html

[6] https://github.com/micropython/micropython/issues/8197

If you really want to engage in the travesty that is shoehorning a high level scripting language into an environment that has 512 bytes of RAM and less clock cycles than an electric toothbrush, there is micropython.

There is some work to implement a common CAN interface in micropython but it's some way off yet: https://github.com/micropython/micropython/pull/13149

https://github.com/raspberrypi/pico-sdk/ links to a PDF about connecting to the interwebs with a pi pico.

micropython/micropython//ports/rp2/boards/RPI_PICO_W: https://github.com/micropython/micropython/tree/master/ports...

raspberrypi/pico-sdk /lib: btstack, cyw43-driver, lwip, mbedtls, tinyusb https://github.com/raspberrypi/pico-sdk/tree/master/lib

raspberrypi/pico-examples//pico_w/wifi/access_point/picow_access_point.c:

https://github.com/raspberrypi/pico-examples/blob/master/pic...

There's an iperf opkg pkg, or is it just netperf (which works with fluent)?

raspberrypi/pico-examples//pico_w/wifi/iperf/picow_iperf.c:

Needed for hobby project, maintained by very small team. Haven't decided on specific microcontroller. Needed for general bit-banging, speed and code size are not priorities.

So far have considered MicroPython [0] [1] and Lua [2] [3], but open for suggestions for others.

What are experiences?

[0] https://micropython.org/

Python is also a general-purpose programming language. It's typically used on desktop / laptop computers. But Micropython is a variant that can be used to program embedded devices.