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Comment by the_duke | Hacker News Reader

But... why??

Edit:

> This paper presents DOPPIO, a JavaScript-based runtime system that makes it possible to run unaltered applications written in generalpurpose languages directly inside the browser.

Someone should really have told them about webassembly...

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The first commit to Doppio was 13 Feb 2012

One year before asm.js appeared, in Mar 2013

Three years before WebAssembly appeared, in June 2015

Five years later, In 2017, WebAssembly still doesn't have a GC and cannot run the Java/Scala/Groovy programs that Doppio was able to run in 2012

Doppio's lineage goes back even further than 2012. A "JVM in JS" was given in Emery Berger's 691ST course in the fall of 2011. My notes show that I submitted my "finished" JVM on October 26, 2011. I say "finished" because it became obvious rather quickly that a lot of things would be difficult if not impossible in JS (like threading and synchronization) and so we negotiated with Emery to come up with a subset of Java that we could reasonably implement for a class project. IIRC, there were 6-8 VMs written that semester.

Doppio proper (the repository you refer to) started during the spring meeting of 691. Those guys went above and beyond the minimal spec we implemented, and they tackled a lot of stuff that we thought was impossible. Thus the research paper.

IIRC, we also had to write a decentralized chat program in JS that semester. That was also "fun".

Yes, I created a HN account just to post this.

Thank you. This is great work from both an engineering and scientific perspective.

The paper was released at least a year before WebAssembly was even announced...

... and a year after WASM's predecessor was announced.

Directly from asm.js FAQ (http://asmjs.org/faq.html):

Q. Can asm.js serve as a VM for managed languages, like the JVM or CLR?

A. Right now, asm.js has no direct access to garbage-collected data; an asm.js program can only interact indirectly with external data via numeric handles. In future versions we intend to introduce garbage collection and structured data based on the ES6 structured binary data API, which will make asm.js an even better target for managed languages.

Just pointing out that the work on what would become WASM was already heavily underway by that point.

This paper was first published in June 09–11 2014 (first commit Feb 11 2014), Webassembly was first announced on June 17 2015.

asm.js that lead to WebAssembly was announced 21st March, 2013.

Doppio relies heavily on the Javascript object model, the asm.js subset of Javascript isn't very relevant.

Webassembly doesn't have GC (yet)

Does doppio actually rely on the JavaScript garbage collector?

yes -- it implements Java objects on top of Javascript objects.

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