Hacker News Reader

Comment by oblio | Hacker News Reader

And it will never happen (ok, maybe "never" is too strong - it will happen 10-15 years from now, at best and even then it will be unstable/unreliable/slow/half baked on some platforms, because reasons). The best we've got is the piece meal approach of HTML/Javascript/CSS.

And before you blame those standards, blame the Unix vendors^W^W, pardon me, the platform owners (Microsoft, Apple, Google).

View on HN

There doesn't seem to be anything unstable about it, even now. I've compiled tons of Rust code to asm.js over the last few months and there's not a single thing that didn't work. Modifying the DOM also works fairly well (you have to write wrappers though). And the code is 10x to 40x faster than the equivalent JS code. And you can run the exact same code natively on tons of platforms too. So it's already quite amazing.

One package that doesn't work yet, last I heard, is regex. That's a big one.

I'm not 100% sure if I tried it in any of my apps, but I think I did, and can't recall it not working. I'll try again soon and will tell you if it works.

Please fill me in too, possibly filling an issue on the regex repo if there's anything I can do to help. (This is the first I'm hearing of the problem.)

I had only heard of it second hand; I thought it was already communicated upstream. Oops!

Why won't it happen? If wasm can talk to the DOM, then you'll still be using HTML and CSS, and wasm in place of JS. There's no reason this couldn't be done already by just compiling to JS, and plenty of languages already do that.

You could also render everything to a canvas to avoid HTML and CSS, but at that point there are a lot of things to re-implement, especially around accessibility.

Well, first of all wasm needs to be implemented in all major browsers on all major platforms for it to be widely adopted. Since the major browser vendors are backing it, that should happen quite soon.

But that's just the initial implementation. It needs to be implemented fully, debugged, optimized and then it needs to trickle down to user devices, including those sold 3-4-5 years ago and still in use.

And then, in the second stage, wasm needs to get DOM access (as far as I know v1 won't have it). See stage 1, all over again.

I'd say that the mass adoption cycle for 1 stage is roughly 5 years (where 80%+ of the browsers out there support a major feature well). So 2 stages x 5 years = 10 years.

Maybe I'm too pessimistic...

Given the history of the web and what I know of the people/companies behind wasm, it seems very likely that there'll be a graceful degradation/shim in the form of a wasm interpreter written in JS/asm.JS (or even a JIT from wasm to one of them), so there'll be no need to wait for all browsers to have implemented it, it just won't live up to its performance on all platforms.

There already is: https://github.com/lukewagner/polyfill-prototype-1

I think you are being too pessimistic about the speed of mass adoption.

On the desktop: Firefox, Chrome and Edge auto-update.

On mobile: Android 4.4+ (over 80% and rising fast) auto-updates its webview component. iOS receives yearly updates that are applied by a very large majority - though Apple's browser development does seem to have stagnated a bit.

So it seems to me that non-updating browsers are going extinct, and that we won't be dealing with another IE6 anytime soon. We're living in the future! :-)

The age of the evergreen-browsers is dawning. Although it will be years before the last corporate holdouts let go of their pinned IE9/IE10/IE11 browsers.

Why is 80% the magic number? 5% would reach more than 100 million people. That's enough to keep a team busy and a product growing while the competition sits on its butt waiting for the next 75%.

There is a shim so you don't need to wait for all the browsers to implement wasm

I hate JS but replacing it with Rust for front end is a bad idea, Rust is a low level systems programming language, it's very suboptimal for high level front end code from productivity standpoint and it adds no value because it's advantages (mem safety with 0 cost abstractions) don't really matter in frontend (JS is super bad at being optimizable but it's still more than sufficiently fast).

Rust is indeed known for memory safety and zero cost abstractions. But there is another side to Rust which is even more interesting - a type system that is almost as powerful as those of functional languages like OCaml and Haskell, but wrapped in approachable imperative syntax.

With such a type system, it is possible to encode the invariants of your application in types (using generics and algebraic data types). Then you can get very close to "if it compiles, it works".

JS, in particular, is the opposite. I am never really convinced that any JS I have written is "correct". It works, until one day it doesn't. This is such a problem that there have been multiple attempts to retrofit type-systems on top of it.

Rust needn't be the only language that brings strong typing to the frontend (Elm has been around for years now). But I think the prospect of speed and correctness both front and back is pretty exciting.

>But there is another side to Rust which is even more interesting - a type system that is almost as powerful as those of functional languages like OCaml and Haskell, but wrapped in approachable imperative syntax.

That type system is pretty verbose because it's aimed at manual memory management which you don't really care about in front end, and the compile times are huge compared to say TypeScript or something along those lines so yeah - I agree static typing is nice - but saying you should use Rust for front-end because it has static typing is like saying every gardener should have an excavator because digging holes with hands sucks - shovels exist.

I don't necessarily disagree with you, but when wasm is fully established I expect to see (another) step change in the complexity of the web. Fully-featured applications, 3D, VR, AR etc. We are on the brink of it already. And beyond a certain complexity (a relatively small amount of complexity, I would argue), a decent type system is essential.

Rust just happens to be well positioned to take advantage of all this.

Are you saying because it can do A it can't do B?

Are A and B mutually exclusive per se or is that just an unfounded assumption?

It's a design trade off. I don't get why people are so pissy about it - Rust makes design choices that are suited for low level systems programming language - but it has a lot of noise and complicated things from high level language stand point, and compile times + debugging + lack of run time tweak-ability make it very unproductive for front end compared to say TS/JS

I use Rust for web 1 year already and I can say it's awesome. Try.

But on the backend, not on the client, I presume? If you've really been deploying Rust over the wire via asm.js, then some commendations are in order for your persistence. :P

Yes, of course. But in parallel I write code in TypeScript (frontend) and after few months performance is equivalent in both languages. Only difference - no runtime errors in Rust.

Are you joking ? You can have hot module replacement in TypeScript meaning you don't even have to refresh the page to get new code in browser - and then you can fire up the REPL and prototype stuff - Rust has to go trough rebuild+redeploy on every iteration - you're saying that's the same speed ?

No. I don't use hot module replacement and I don't like this idea. And I don't prototype things often - maybe once or 2 per year - my contracts are usually long enough. It's all personal, as you see.

I'm saying that to implement feature in Rust takes same time as in Typescript or PHP (as PHP is a server side language also and comparison is more illustrative).

memory safety isn't the only advantage.

0 cost abstractions do matter a bit. In general abstractions let you do high level programming in lower level languages.

The type system matters a lot.

I used to do a lot of scripting. One thing I really missed was having a good static type system. These days I miss ADT enums in all languages.

Scripting is already moving in the direction of being more type safe (typescript, python type annotations), which is awesome, but I'd love to use something like Rust in that sphere.

I love JS (pretty unpopular opinion here on HN) and I love Rust also and I'm not convinced using Rust on front-end tasks would have any benefits. Yet, I strongly disagree with you on this point :

> Rust is a low level systems programming language, it's very suboptimal for high level front end code from productivity standpoint

Rust's type system is wonderful, and it's a real productivity boost. Fortunately people at Facebook developed an equivalent for JavaScript [1] because living without it would be really hard for me now. Furthermore, Rust offers a lot of syntactic sugar that makes it feel like a really high level language (compared to C, Go or even JavaScript pre-ES6 for instance).

>it's advantages (mem safety with 0 cost abstractions) don't really matter in frontend

It's indeed one of Rust selling point (especially for people coming from a C background) but it's not the only one. My favorite being the data-race free parallelism. I don't know the current status of multi threading in wasm, but being able to take advantage of all the cores of mobile devices could really help front-end frameworks.

[1]: http://flowtype.org, it's not inspired by Rust but inspired by OCaml, which also inspired Rust.

>Rust's type system is wonderful, and it's a real productivity boost.

Rust type system is verbose compared to higher level languages and it lacks a lot of the things that make higher level languages productive. It just focuses on low level code - which is good - but you wouldn't use it in place of C#, you would use it instead of C++, and you don't want to write GUI code in C++ either (even Qt uses JS for the frontend)

>My favorite being the data-race free parallelism.

Also mostly irrelevant in front end since you're dealing with single threaded event loops and doing parallel work that talks to UI thread is easy. Stuff that needs to do work in parallel can be written in Rust and talk to front end via FFI or RPC.

> even Qt uses JS for the frontend

Only if you use QtQuick. The traditional QWidget API is C++ all the way.

If you don't like it, you don't have to use it. The beauty of WebAssembly is that it can be targeted by so many other things. Finally, we can let JS sink or swim on its own, without being propped by an artificial monopoly on the web frontend scripting...

Reply on news.ycombinator.com