I'd like to echo the sentiments here: I think this would be great.
I think good scripting language support is very important for Mynewt.
Most of the newer chipsets (like the NRF52), have enough RAM and Flash,
that you can run the OS, Bluetooth stack, and still have 256KB or more
left over for a fairly complex application. Also, you could imagine the
Mynewt OS being preloaded on boards, and then someone uploading code to
them using firmata -- whether it be Javascript, Python or Wiring code.
This would provide a simple programming model, but enable full OS
support -- and I think this could be easily integrated into PlatformIO
or the Arduino IDE.
Additionally, if you look at a lot of the popular scripting languages
(Espruino, Micropython, Wiring) -- they end up having to implement a
whole bunch of things better left to the operating system (HAL, BSP,
Network stacks, Drivers.) If they can plug in to Mynewt, they don't
have to worry about any of that.
I don't know how much time I have in the next couple of months to devote
to this, but count me in on joining in the development/helping to
support as much as possible. I'll definitely test things :-)
Some thoughts on the various options for Javascript. This is meant as
more of a dump of what I've looked at / been thinking about in case you
find it useful:
- Jerryscript: Apache 2 license, which is critical should we want to
bundle it with Apache Mynewt. It looks like a good Javascript
interpreter, my only concern is that it separates the compile & run
stages, and I'm not sure how memory efficient the compiler is.
What's very nice is that Jerryscript is just the Javascript engine, and
it looks fairly easy to write custom extensions for it. If somebody
could evaluate the memory usage when parsing, it would be great.
- Espruino: Espruino's popularity is, I think, due to the fact that it
provides a full operating environment, not just the Javascript engine
itself. It looks pretty solid, and both the parser and engine have been
shown to run on exactly the microcontrollers we've been targeting.
Espruino uses the MPL, and has a copy-left license, which is somewhat
more restrictive then the Apache license. It is also less complete than
Jerryscript, from what I can see.
- v7 is GPL.
- Javascript to Lua compilation: We already support Lua, and it's an
incredibly efficient virtual machine for these small environments.
Since Javascript is made to be compiled, and recompiled -- we could
support Javascript today through a JS->Lua compiler. This would also
mean we only needed to do the language bindings once, and could run both
options.
The downside is, what actually runs is Lua, not Javascript. There
wouldn't be a Javascript console on the device.
(compilers: https://github.com/PaulBernier/castl,
https://www.npmjs.com/package/lua-colony)
I personally like the Jerryscript option the best (thus far), due to the
license, and the fact that it's just a JS engine. Followed probably by
the JS->Lua compiler (which, with one effort gets us both Lua & JS
support.)
I don't imagine getting Jerryscript ported will be a whole bunch of
work, it's just importing it into our build system. I think the big
effort will be around making sure we choose the right OS APIs. I think
it will be good to look at a few things on the OS side, to make it
easier for the Javascript integration:
- Ensuring our BLE APIs are designed to map easily to the JS interpreter
- Adding some form of sensor API, to abstract access to common sensors
- Adding a bunch of higher level drivers (above the HAL), that provide
simpler APIs to access hardware functions -- that we then map into JS.
But first things first, just getting the interpreter up & running &
talking to the OS would be awesome!
Sterling
On 5/25/16 7:57 PM, David Moshal wrote:
Ok David, I'm game.
I'm familiar with NodeJs, have mission critical NodeJs software in
production, with no downtime, since 2011.
I don't know what platforms MyNewt runs on, but you're going to need
significant horse power to run the NodeJs V8 engine. I've run NodeJs on
the Arduino YUN (400Mhz, 64Mb ram), using Linux, so that's probably the
ballpark, spec-wise.
On the other hand, if what you want is a Javascript engine in general, then
there are at least half a dozen alternatives. I've used Espruino, on its
own Pico board (STM32f401), and on ESP-8266 (32bit Tensilca core). There
are others, V7, TinyJS, JerryScript, etc.
So, what are the next steps? What's the best IDE environment to use (I'm on
OSX).
Can Platform.IO be used, or is that a competitor?
Dave
On Wed, May 25, 2016 at 4:56 PM, David G. Simmons <santa...@mac.com> wrote:
Maybe we should work together! My goal is to get Javascript (actually
Node.js) running on MyNewt. I have C experience, but there is lots to do in
order to make this work the way I need it to.
Best regards,
dg
On May 25, 2016, at 6:49 PM, David Moshal <dmos...@gmail.com> wrote:
Thanks, actually I've been using both lua and JavaScript (espruino) on
esp8266-12e for a couple months.
As mentioned to Sterling at the maker faire last weekemd, my interest in
mynewt is actually to try and embedded js on the emw3165, which has the
stm32f411 plus wifi.
However I have zero experience with c, and specifically with the tool
chain
and use setup.
That's the part of really like help with.
--
David G. Simmons
(919) 534-5099
Web • Blog • Linkedin • Twitter • GitHub
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