Mozilla can produce near-native performance on the Web

Who knows how fast Emscripten+asm.js-compiled DartVM would be compared to Dart2JS in 2013? I don't know yet, and apparently neither do you. JITs can be tricky, but @azakai is having good results with Emscripten+asm.js'ed LuaJIT2.

What I wrote 593+ days ago was about the Dash memo's Microsoft-like strategy. My point then was not that it couldn't ever be defeated by something like our work on asm.js and Emscripten. Never say never. My point rather was that the Dash strategy intentionally used Google's big resources to push a gratuitously non-standards-based agenda at the expense of its Web-standards-based efforts.

Indeed, since then it has become clear that Google miscalculated. Dart even gave up bignums (the int type) to support Dart2JS/DartVM equivalence, which I think is a mistake. Bignums are actually on the JS standards-based agenda:

http://wiki.ecmascript.org/doku.php?id=strawman:bignums

http://wiki.ecmascript.org/doku.php?id=strawman:value_object...

See also

https://bugzilla.mozilla.org/show_bug.cgi?id=749786

Given all the time that has passed since 2010, Google champions in Ecma TC39 could easily have worked bignums into ES7 if not ES6.

At a higher level, by over-investing in Dart and under-investing in JS (the V8 team was moved from Aarhus to Munich and with the no-remoties rule had to be rebuilt), Google has missed opportunities such as game-industry work we announced at GDC with Epic. This is "ok", it's their choice, but I still say that it is inherently much more fragmenting than any optimization of the asm.js kind, and that it under-serves the standards-based Web.

Maybe in a few years we can evolve JS to incorporate whatever helps DartVM beat Dart2JS, if there's any gap left. However, the idea that mutable global objects in JS necessarily mean VM-snapshotting is impossible is simply false. On the other hand, do we really need VM snapshots to speed up gmail startup? LOL!

/be

You can't simply asm.js'fy LuaJIT2 because it has an interpreter hand written in assembly and it generates native code to achieve peak performance. You can only asm.js'fy a normal Lua interpreter which is up to 64x slower than LuaJIT on benchmarks, when compared natively. So asm.js'fied Lua will be up to 128x slower. Does not sound that impressive...

Your green-colored id says you are new here, and yet unwilling to do basic research in HN on the topic you ask about. I'll take this in the "Dear LazyWeb" spirit, assume that you are not trolling, and give some links. First, one of a few obvious searches:

https://www.google.com/search?q=site:news.ycombinator.com+pn...

From the results, an entry point into a deep thread, posted by Maciej Stachowiak of Apple:

https://news.ycombinator.com/item?id=4648045

Further in this sub-thread, I comment on the loaded language used to open-wash NaCl and portray critics of it as haters:

https://news.ycombinator.com/item?id=4650689

Back to your comment: "It's based on open source tools" is true of Emscripten too.

The bit about "can be easily integrated into any browser" is false due to Pepper, the large new target runtime for *NaCl. Pepper is a non-standard and unspecified-except-by-C++-source plugin API abstracting over both the OS and WebKit -- now Blink -- internals.

To make such an airy assertion in an under-researched comment makes me suspect that you don't know that much about either PNaCl or "any browser". So why did you make that confident-sounding claim?

These days, large apps are written in JS, even by hand. GWT is not growing much from what I can tell, compared to its salad days. Closure is used the most within Google, and Dart has yet to replace Google's use of GWT + Closure.

Outside Google, hundreds of languages compile to JS (http://altjs.org/). CoffeeScript is doing well still. TypeScript is Microsoft's answer to Dart, and more intentionally aligned with the evolving JS standard.

"Does Mozilla has any plans to improve the situation here?"

Have you heard of ES4? Mozillans including yours truly poured years into it, based on the belief that programming-in-the-large required features going back to "JS2" in 1999 (designed by Waldemar Horwat), such as classes with fixed fields and bound methods, packages, etc.

Some of the particulars in ES4 didn't pan out (but could have been fixed with enough time and work). Others are very much like equivalent bits of Dart. One troublesome idea, namespaces (after Common Lisp symbol packages) could not be rescued.

But ES4 failed, in part due to objections from Microsofties (one now at Mozilla) and Googlers. In a Microsoft Channel 9 interview with Lars Bak and Anders Hejlsberg, Lars and Anders both professed to like the direction of ES4 and wondered why it failed. _Quel_ irony!

As always, Mozilla's plans to improve the situation involve building consensus on championed designs by one or two people, in the standards bodies, and prototyping as we specify. This is bearing fruit in ES6 and the rest of the "Harmony era" editions (ES7 is being strawman spec'ed too now; both versions have partial prototypes under way).

Founding Harmony email (on the demise of ES4):

https://mail.mozilla.org/pipermail/es-discuss/2008-August/00...

A talk I gave last fall on ES6 and beyond.

http://brendaneich.github.io/Strange-Loop-2012/#/

For programming in the large, ES6 offers modules, classes, let, const, maps, sets, weak-maps, and many smaller affordances. I hope this helps. Even more is possible, if only the browser vendors and others invested in JS choose to keep working on evolving the language.

Look around you at the Web: all the top sites use JS heavily and without "heroic efforts" compared to Java (dead on the client) or .NET (WPF is dead too).

If the old big-OO-frameworks really conferred such huge fitness advantages over JS, you would not see them dead on the client. They would have been used, and their plugins would have been supported better by the plugin vendors.

JS these days has a lot going for it, including IntelliJ-style IDEs (Cloud 9 offers one) and not-too-OO-or-huge frameworks.

/be

>To make such an airy assertion in an under-researched comment makes me suspect that you don't know that much about either PNaCl or "any browser". So why did you make that confident-sounding claim? Unfortunately, I can evaluate technologies according only to my experience and knowledge. According to my limited knowledge and experience, what PNaCl evolves to seems like the way to go: I can use whatever language I like to write code; I can utilize resources of computers efficiently; The code is performed in a sandbox; It's based on non proprietary standards (I mean LLVM, not Pepper).

>The bit about "can be easily integrated into any browser" is false due to Pepper, the large new target runtime for *NaCl. Pepper is a non-standard and unspecified-except-by-C++-source plugin API abstracting over both the OS and WebKit -- now Blink -- internals. It's a new technology, how is it supposed to be standardized? IMO, it's better to create some implementation, and then, to standardize it, not vice versa. AFAIU, how Pepper API works, the application is run as a separate process, operating system APIs are isolated with Pepper API and there's a way to post JavaScript code to be executed in browser's event dispatch thread to update and query DOM. This API seems to be narrow and generic enough to be supported in any browser. Code which provides OS services can be reused from code as is, the only variable part is DOM interaction, which is narrow enough to be supported in any browser.

>Have you heard of ES4? Mozillans including yours truly poured years into it, based on the belief that programming-in-the-large required features going back to "JS2" in 1999 (designed by Waldemar Horwat), such as classes with fixed fields and bound methods, packages, etc. I closely monitored what have been happening to Harmony, and it was obvious that this effort wouldn't have panned out. There were just too many complex features to be implemented (for example, generics) in a single release.

>These days, large apps are written in JS, even by hand. GWT is not growing much from what I can tell, compared to its salad days. Closure is used the most within Google, and Dart has yet to replace Google's use of GWT + Closure. I myself write large scale JS apps with GWT. It's really painful but if it was written in plain JavaScript it would have been much worse (I think it event would have been impossible to write and debug code which I write). GWT has its disadvantages: compilation time is very slow, I don't have access to many APIs (mainly reflection and dynamic code loading), devmode for all browsers but Firefox is awfully slow. But despite its disadvantages, it's the best tool for my job (I debug most of the code in JVM, by abstracting away access to DOM).

Both Mozilla and Google agree on goodness of LLVM, since both PNaCl, and asm.js toolchain are based on it. Google has solved the problem of efficiently representing LLVM in a platform independent way and safely executing it in a sandboxed environment. Why not create a PNaCl and LLVM based standard to allow, efficient execution of code? Is it so difficult?

Mozilla promotes asm.js as a "standard compliant" way to do the same thing as PNaCl. However, there are a lot of disadvantages in this approach: asm.js is text based and very verbose, binary format will save a lot of traffic; asm.js doesn't provide access to SIMD and multi-threading which are crucial for good performance; asm.js won't work out of the box, it requiress some effort to support on the side of browser vendors, for example, the only browser where Unreal demo initially worked was Firefox nightly build. Is it so hard to find a consensus among browser vendors (or at least Mozilla and Google) in this respect?