[pypy-dev] Feedback on Graduate School Research Idea Using Pypy

[Yury V. Zaytsev]

An experimental WebAssembly backend is definitively an interesting idea, 
but as you have realised, to get PyPy running in the browser, it's not 
necessarily needed, as you can compile C to WebAssembly instead.

Sure, a native backend sounds nicer, but from my PoV the real performance 
questions lie elsewhere - so you've got an interpreter running under V8, 
what next? Obviously, it's not performing very well. What are the 
possibilities?

Are you going to try to restructure the interpreter in a way, that your 
language sematics become clearer to V8 so to say and it will be able to 
more or less JIT your interpreter directly? Is it even possible, with 
custom backend by avoiding Emscripten or otherwise?

Or maybe it makes sense to first write a WebAssembly JIT backend keeping 
the rest of the messy RPython -> C -> Emscripten -> WebAssembly toolchain 
in place, and study how to JITs (PyPy generated JIT and V8 JIT) interact? 
Is this interaction meaningful or harmful? Can it be turned into 
productive cooperation?

These are open questions, I don't know the answers, but what I want to say 
is that just being able to port interpreters to the browser is already 
possible via Emscripten, and in the context of PyPy there are other 
(I think) much more interesting questions to study.

... and I wouldn't muddy the waters with Python 3 transition, working on 
the questions above there is enough material for several PhDs, not even 
speaking of a master thesis :-)

On Tue, 12 Nov 2019, yun bao wrote:

> I took a look at PyPyJS.  I also spoke with some folks at Mozilla, and have become very interested in WebAssembly.  I think having
> WebAssembly as a target for RPython would be very useful.  Based on what I've learned recently, it should be possible to write an
> interpreter in RPython, translate it to C, then use Emscripten to compile that to WebAssembly.  However, if there was a WebAssembly backend
> for RPython, it would be possible to build interpreters than run directly in the browser (potentially even PyPy.).  That seems like an
> avenue worth investigating, doesn't it?  I think while doing that, it would be worth getting RPython compatible with Python 3.  By the way,
> these are things I'm thinking about doing myself, not recommendations to any of you.  I'm still working on a solid thesis idea for my
> Master's.  
> 
> On Sat, Nov 9, 2019 at 12:25 AM Yury V. Zaytsev <yury at shurup.com> wrote:
>       Maybe you should start by having a look at PyPyJS and then exploring WebAssembly:
> https://github.com/pypyjs/pypyjs
> 
> Sent from my iPad
>
>       On 9. Nov 2019, at 03:40, yun bao <dayunbao at gmail.com> wrote:
>
>       Hi,
> I'm planning to go to grad school for a Master's.  I'm thinking about researching something related to getting Python running
> in a web browser.  All of the current implementations that allow you to do that either transpile Python to JavaScript ahead of
> time, or do some kind of on-the-fly conversion from Python to JavaScript.  I'd like to write an actual Python engine that will
> run in the browser.  As I've been mulling over this idea, I read about Pypy.  Given my limited knowledge of this domain
> (programming language engines that run in the browser) and the exact nature of the problem, Pypy seems like the best route to
> achieving this.  I'm still very much in the early stages of fleshing this idea out, and besides the typical undergraduate
> Programming Language class, I haven't done much in the way of programming language design or anything compiler related.  So I
> have A LOT to learn.  But I was hoping some of you who are Pypy experts could give me a bit of advice on the feasibility of
> what I'm considering.
> 
> Thank you,
> 
> Andrew
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>

-- 
Sincerely yours,
Yury V. Zaytsev