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Walt: JavaScript-like syntax for WebAssembly (github.com)
278 points by jedisct1 66 days ago | hide | past | web | favorite | 99 comments



I was excited at first. Compile Javascript like code into WebAssembly text format? Zero dependencies? Count me in!

I thought: Great! Let's try it! So how do I use it? How do I hand over a string of Walt and get a string of WebAssemblyText back?

I though there is a javascript file somewhere in the project that has a compile() function that does that.

And then I clicked on the Quick Start Guide and it looks much more complicated. It tells me to install node, npm, webpack, walt-compiler, walt-loader... set up a project with a certain structure, create a landing page...

Help :) That's not what I want. I just want a function that takes a string and returns a string.

Would it be possible to just offer a javascript file to be used directly in the Browser? That exports a function which translates your JS dialect to WasmText?

Is that file somewhere in there maybe?


Yes, that's the compiler: https://github.com/ballercat/walt/tree/master/packages/walt-...

It's written in JS so you'll need node to run it, and npm is a package manager for node so you should use that to install and call it.

If you just want a hosted site to play with code, it's linked right at the top: https://ballercat.github.io/walt/


    It's written in JS so you'll need node to run it
I happily run JS in my browser all day. Why do I need node for this code?


Because different runtimes support different features and performance (like dealing with files and disk access) but I already posted the link for the browser version in that comment.


I think that's not quite what was asked for. What was asked for is one JS file with a function that takes a string and returns a string. Not a node package, not a website. Check out Three.js, it's a big library which can be used as one file three.min.js.


If you check the `dist` folder within the linked Git repository you can see a `walt.min.js` file[0]. You should be able to include that file and try out the package in your browser in a similar way to how you use `three.min.js`.

[0] https://github.com/ballercat/walt/blob/master/packages/walt-...



Maybe so you can deliver precompiled wasm to a browser rather than having to deliver the source and a compiler?


You don't need node to compile WASM or deliver it to the browser, either.

The only reason this "needs" NPM is because it's become convention that all javascript projects need NPM and some related toolchain regardless of their complexity.


No, the convention is that Javascript projects are distributed as source rather than as "binaries" (single minified JS files.) Source code generally needs a build tool. NPM is a build tool.


> Why do I need node for this code?

The next paragraph of the comment you replied to answers that — you don’t, you can use https://ballercat.github.io/walt/ in your browser.



Awesome! Thanks man!

This is what makes Hacker News great!


Actually, check again! I just updated it to NOT use wabt. Walt-compiler has its own semantic printer, so its output is more readable.

And yes! I think answering these kind of simple questions is important, so thanks for asking them.


Even better.

I'm already having fun with it.


It doesn't translate to wasm text format, but to wasm binary format. The walt-compiler (https://github.com/ballercat/walt/tree/master/packages/walt-...) readme shows how to use it to compile text into a a buffer which you can write to disk or instantiate into a webassembly module.


    It doesn't translate to wasm text format,
    but to wasm binary format.
Oh, ok. That is interesting too. But I would have liked to build a tool where I type Walt on the left and see the resulting WASMtext on the right. So this seems to not be a solution for that.


That tool already exists: https://ballercat.github.io/walt/ - though you have to switch 'tabs' to see the WASM code.


Yes, I saw that.

It's not the interface that I would like to use. I want to write Walt on the left and instantly see the WasmT on the right.

Also, that tool does not work here. It gives me 'Uncaught ReferenceError: getAST is not defined' as soon as I type something in the code tab.


What? Just use wasm2wat [1] and you’ll get the text format.

[1] https://github.com/WebAssembly/wabt


Your argument is valid, the QuickStart example isn’t wrong though. Webpack is somewhat the bundling standard in front end. What they showed, I can easily get it working in a large project without a lot of kungfu.

If you want the walt->wasm function, it’s usually the loader.

And yes, you can invoke the loader standalone.

Perhaps they should give a much simpler example and then later a webpack example.

It’s open source, open a PR may be?


These look less like questions about the project and more like feature requests.

Perhaps you should try unpkg:

    <script src="https://unpkg.com/walt-compile"></script>
And if that doesn't work, perhaps you can submit an issue or a PR.


Go to https://flems.io/walt-compiler

You can then play with the `Walt` global.


What's the difference between this and something like AssemblyScript?: https://github.com/AssemblyScript/assemblyscript

EDIT: I see that this project actually existed slightly before AssemblyScript. Still seems like two very similar projects.


I wrote/maintain Walt. This question comes up a bunch.

The two projects are really similar no doubt. I can't speak for AssemblyScript, but my own motivation was simple. I wanted to learn WebAssembly and I wanted an accessible platform to do so with. At the time this wasn't really possible, tools like emscripten took forever to set up and were clunky to use. Plus I knew C already, I wanted to learn WebAssembly instead.

So where Walt is an attempt to write WebAssembly with a familiar syntax, AssemblyScript is an attempt to compile TypeScript to WebAssembly. To do so AssemblyScript comes with many more niceties/features out of the box IIRC, like optional(?) GC for example. Walt makes no such attempts and takes a more DIY approach.

Walt also has language extensions, via customizable syntax and compiler pipeline, where AssemblyScript is a TypeScript compiler more or less. My hope is that this allows for a babel-like situation for WebAssembly in the future via the tooling setup for Walt. I don't think this is a goal of AssemblyScript.


> Walt also has language extensions

IMO this is a good decision. I much prefer a platform with a small API than I can personally extend over a large platform that has specific customization options or lots of extra features that all just "kind of" solve whatever problem I have.

Reading this makes me more interested in the project than I was before.

One quick recommendation, it was kind of hard to find the documentation for the Webpack free compiler (https://www.npmjs.com/package/walt-compiler). This is purely anecdotal, but I suspect that at least some of the people who are turned on by having a low-level library that doesn't include Typescript niceties will be turned off by seeing the quick-start immediately say to install Webpack. Might be a good idea to have the compiler documentation inside the wiki alongside the quick-start?


[flagged]


> The whole point of WebAssembly was to find some way to get away from JavaScript

The goal is to "Define a portable, size- and load-time-efficient binary format to serve as a compilation target which can be compiled to execute at native speed by taking advantage of common hardware capabilities...."[0].

[0] https://webassembly.org/docs/high-level-goals/


WASM is then the new JVM. Birth and Death of Javascript indeed.


Everything old is new again, and the Wheel of Time turns, and ages come and pass, leaving memories that become legend. Legends fade to myth, and even myth is long forgotten when the Age that gave it birth comes again. In one Age, called the third age by some, an Age yet to come, an age long past, a virtual machine specification was created in an attempt to achieve the goal of write-once, run everywhere code. The specification was not the beginning. There are neither beginnings or endings to the turning of the Wheel of Time. But it was a beginning.


Just like CPUs.

In the beginning Assembly became bytecode and CPUs included interpreters via microcode, then everything was supposed to be executed directly by hardware gates, now Assembly has become another form of bytecode and all major CPUs have reverted back to microcode.

Same applies to GPUs.

Everything old is new again, indeed.


Thanks for bringing some poetry to tech land :)


What a weird argument. C is not "better" than Javascript, it is vastly worse for the vast majority of current Javascript uses - where raw performance is a less important consideration than development time.

Javascript is far from perfect, but it has improved by leaps and bounds the last few years. WebAssembly is great, but a variant of Javascript or other high-level languages will continue to dominate web development, not C. People aren't going to "escape" from Javascript to C, except certain niches where performance is vital.


I disagree about "better", but...

If you like your JavaScript, you can keep your JavaScript. You have no reason to care about WebAssembly. Why would you build a JavaScript imitation on WebAssembly when you can just use JavaScipt?

WebAssembly is for the rest of us.


That's the thing though. We are all "us" here. We can all compile whatever we want to WebAssembly, that's the point of WebAssembly. One way of doing things doesn't take away from another.


It's not a JavaScript imitation. This is a JavaScript-like syntax for writing WebAssembly. Other than that, (excepting the closure helper) it's 1-to-1 WebAssembly.

Not everyone enjoys writing verbose S-Expressions [1], even if it makes for a good canonical format.

If you despise JavaScript so much that you can't bear the thought of something that vaguely looks like JavaScript, then don't worry there are other "skins" for writing WebAssembly [2-4] and it should not be too hard to write your own.

Finally, nobody owns WebAssembly. It's for clever people like yourself just as much as it is for dirty JavaScript programmers like me.

[1] https://developer.mozilla.org/en-US/docs/WebAssembly/Text_fo...

[2] https://github.com/tmcw/wah

[3] https://github.com/serprex/luwa

[4] https://medium.com/cirru-project/webassembly-s-expression-an...


You might like a JavaScript-like language but want to get rid of the garbage collector, or work closer to the bare metal than Javascript currently allows.

WebAssembly is for everyone.


Escaping JavaScript is not a perspective shared by all (most?), though.

It's has been a weird and interesting project, but that's not really a bad thing is it.


You'll have to excuse HN Guy that assumes that every project on GitHub is done to try and take over the world and not because, you know, learning is fun. So keep on doing weird things with your weird and awesome language.


I may be in the minority then: one of the big advantages, for me, of WASM is that I can use not-Javascript in the browser. Some of the issues I have with JS are an artifact of being one of the first things to run in the browser (e.g. atrocious standard library) and some are just baked in poor designs (e.g. implicit type casting, == vs ===).

Oh gosh, let's not forget what happens when you try to use map and parseInt together.


[‘1’,’2’,’3’,’4’,’5’,’6’,’7’,’8’,’9’,’10’].map(d => parseInt(d));

Returns

[1,2,3,4,5,6,7,8,9,10]


Sure, but you're putting a workaround in – there really shouldn't be any need for that no-op arrow function. But you do actually need it in order to drop all but the first arguments.

This is simple, straightforward, and wrong:

    ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10"].map(parseInt)
This doesn't work because map() stuffs a counter into the second argument of parseInt(), which is expecting a radix for its second argument. So the iterations of the map go like this:

    parseInt("1", 0)
    parseInt("2", 1)
    parseInt("3", 2)
…and so on, which obviously gives garbage results. JavaScript is littered with these kinds of weird edge cases. Even your example with the workaround isn't 100% reliable, it's browser-dependent – when you have leading zeros in your strings, some browsers will interpret them as octal, and some won't.


so what is your problem with all this? that these functions have both provided a flexible interface for use cases that are not this single one?


> browser-dependent

Language version dependent rather than browser dependent.

It may seem the same (after all, different browsers implement different versions of the language), but it's a bit different, if you say 'browser-dependent' it makes it sound like there is no standard when in fact, the leading zero behaviour hasn't been the case since ecmascript 5. You'll struggle to find a browser in common use that doesn't support at least ecmascript 5. It's as browser-dependent as the array.map function which was added at the same time.

Your example code would never have the leading 0 problem since you're using array.map and array.map didn't exist in the engines that had that leading 0 'feature'.


I'd expect your example to return a syntax error as those aren't single or double quotes. Try:

["1", "2", "3", "4", "5", "6", "7", "8", "9", "10"].map(parseInt);


Backticks are used for template literals. Try evaluating `2 + 2 = ${2 + 2}`.


Those weren't backticks (`) either. They were "smart" quotes (’ -- you may need a different font to view the differences more readily ’ vs ').


But you understood what they meant right?


From a quick glance, it looks like AssemblyScript compiles TypeScript, whereas Walt uses its own dialect of JS with WebAssembly types.


A quick look at a sample .assembly file [0], make it look like a very different language from TypeScript.

That said, the familiar tooling, editor support, are wins over other WASM options.

[0] https://github.com/AssemblyScript/assemblyscript/blob/master...


I help out every once and a while on the AssemblyScript team with like issues, docs, and things. And made wasmboy, which uses AssemblyScript: https://github.com/torch2424/wasmBoy

But that being said, usually when people are interested in the language, we usually direct them to the "n-body" example: https://github.com/AssemblyScript/assemblyscript/blob/master... . Which kind of looks more typescript-y :)

Also, just to stay on topic, I think walt is awesome. Stoked to see so many projects coming up with a "Wasm for JS devs" approach/story.


Apart from the explicit number types (`i32` instead of `number`, etc.) it looks like standard typescript. What looks different to you?


Incredibly, the segment below is valid TypeScript.

    @inline
    function rot(x: u32, y: u32, v: u32): void {
      var a = max<i32>((v >>> 24) - BIT_ROT, 0);
      set(x, y, (a << 24) | (v & 0x00ffffff));
    }

You must be working on a different set of problems than me to be able to identify this as vanilla TypeScript.

Not given the context of a file extension, I would forgive anyone for mistaking this to be some kind of low level driver code and be confused on source language.

It is so impressive that this is valid TS though!

[edit: code formatting]


I've been going with Lua for writing raw webassembly

Assembler setup: https://github.com/serprex/luwa/blob/master/rt/make.lua Resulting code for a gc looks like this: https://github.com/serprex/luwa/blob/master/rt/gc.lua

& it leaves the full Lua language at my disposal for metaproramming. At the end of a day a human usable assembler needs to be a macro assembler

It'd be neat to have a JS macroassembler, could then have the host browser runtime compile wasm modules dynamically


> Resulting code for a gc looks like this: https://github.com/serprex/luwa/blob/master/rt/gc.lua

Nice! That's a compact gc, perfect for browsers.


> It'd be neat to have a JS macroassembler, could then have the host browser runtime compile wasm modules dynamically

Use fengari (https://fengari.io/) to run your lua assembler?


Lua is fantastic.


Are people really editing .wat files by hand to eek out the last bit of performance? Seems like you would need instruction level profiling to do it justice

Wasabi: A Framework for Dynamically Analyzing WebAssembly

https://arxiv.org/pdf/1808.10652.pdf


Do web assembly files really have a .wat extension? This can't not be an easter egg reference to the famous talk, right? :)


Should have gone with .wtf. WebAssembly Text Format.


.wtf will always be Warcraft Text Files for me. Nothing like editing that Config.wtf file when playing WoW...


Binary size would probably be the main thing you'd want to optimize for. Which, at least a few months ago when I tried the wasm32 target in rustc, is a big issue.


Fascinating! Serious question: could this turn JavaScript (technically Walt) into a serious language for scientific computation? That now runs in any browser?

E.g. Python is used a lot together with NumPy/SciPy, but for performance the actual computation in NumPy/SciPy is done in C since Python is too slow. Would it be possible to create Walt-native versions of NumPy and SciPy... e.g. NumWalt and SciWalt? Or even Jupyter notebooks based on Walt?


You could just port the C libraries that Python uses.

You might want to check that you’re actually gaining any performance, the JIT compilations of JavaScript aren’t often slow.


Would it not be easier to take a language with existing libraries (e.g. Julia, C++) and make it compilable to WASM?

Or even figure out how to run a Python interpreter + WASM-compiled C extensions together to be able to use Numpy, Scipy, etc.


Not really, you would be better off running that code as GLSL shaders on the GPU.


This looks great. I've been looking for a project like this for a while - a simple language in which I can write hot code and compile it straight to web assembly for use in existing node and web projects.

However, I wonder whether Walt is markedly faster than JIT-compiled javascript? Have you benchmarked the performance gain?


I have not, this has been requested quite a bit though. My focus is currently on making sure the toolchain is stable and performant itself. It's likely that the performance of the compiled code is on par with other wasm vs JS comparisons though.


Superb! I would love to see native programs being ported using traditional JS to the browser, perhaps this is a step closer for a clone of Photoshop in the open web!

I like the progress of where webassembly is heading! :)


This is amazing. Yes! I’ve always wanted something like this.

I wonder if we could make a boiled down typescript language server that would give excellent code completion and squiggles for Walt.


Full circle?


Glad I took part of this project early and got the possibility to focus it to great goals


[flagged]


Where did you get that idea? It's not a design goal of WebAssembly: https://webassembly.org/

WebAssembly's goal is to provide a simple VM with performance good enough for the web to compete with native programs and to unlock use cases that are not possible to run efficiently in JavaScript.

The syntax that the developer see is totally irrelevant here.


He not only mentioned syntax but design too. Clearly JavaScript's lack of int (for example, to mention a design decision of JS) is one of the reasons of its poor performance, not to mention its weak typing approach.


There is no lack of int in Walt.


So it's not really JavaScript??? lol


Exactly.


Programming languages are tools, not religions. If a project like this can help people use and understand their tools that is a good thing. Reacting as if the infidel language is defiling the sacred is absurd and indefensible from a practical standpoint.


Well yes... unless you realize that ours is a fashion-driven industry, where technical choices are not made based on technical merits but via a popularity contest. From a practical standpoint, complaining about propagation of bad choices is absolutely defensible.

Or, to put in another way: today you don't complain about crap tech pushing out good tech, tomorrow half of the jobs in your field require you work with the crap tech.


[flagged]


Are you seriously hung up on keywords? Also, you are not required to use "let"...


[flagged]


If you want to troll you should be more subtle about it. Or at least have the courage to use your main account rather than a throwaway


> language that requires the "let" keyword is absurd and indefensible

I would seriously like to see you defend this viewpoint.


Then you will wipeout a big list of programming languages, given how many use let for assignments.


While I have similar feelings, I also think the mark of success for WebAssembly will be if it succeeds in freeing developers to do web stuff in the language of their choice.

Even if that choice is a familiar JavaScript-like language, it still proves the point that the web is now open to whatever the developer wants. So in that sense, I applaud and welcome things like this.

Please do port all of most-hated languages to run with WebAssembly and create new ones that I also don't like. It more or less means that languages I love can be ported and that new ones I will love can be created.


Thanks, I thought nobody would say this...


[flagged]


We detached this subthread from https://news.ycombinator.com/item?id=18190075 and marked it off-topic.


Dismissive non-constructive feedback about projects like this is stupid and IMHO makes people not want to post their projects here.

Your statement and question could have been conveyed like this:

> From my perspective this looks a lot like ASM.js implemented on top of web assembly, but web assembly was meant to replace ASM.js?

The difference is that "congratulations I guess" makes your entire statement and question blatantly communicate "what you did is worthless" when clearly the author had _some_ valid reason to do it, otherwise they wouldn't have.


> Dismissive non-constructive feedback about projects like this is stupid and IMHO makes people not want to post their projects here.

Well, you can interpret my comment as "stupid", which is your right, but it wasn't my intent. And your rebuttal wasn't constructive either. It would have been more useful to highlight the differences between that project and ASM.js. Nowhere in my message I described that project at "worthless", it's your interpretation and it's just wrong IMHO.


The response explained why your post was not great and then elaborated on how you could have done it better. That’s pretty much the text book definition of constructive.


> The response explained why your post was not great and then elaborated on how you could have done it better. That’s pretty much the text book definition of constructive.

Since when personal attacks are deemed constructive? There is nothing constructive in his patronizing comment. How about one of you formulates a technical rebuttal to my initial statement as I asked and you quit being meta?


You both could've done better in constructing your responses. He explained why yours was lacking, you explained why his was lacking. You both made valid points.

As for actually answering your question, probably only Walt's author could answer that. Unfortunately, due to your condescending choice of phrasing, he may choose to not engage in discussion with you, thinking that you're not sincerely interested in his answer.

I hope he looks past that and does answer you, as I'm sure others are wondering similarly.


Doesn't JavaScript compile down to WebAss? Isn't that the point?


WASM is a very new standard. Some JavaScript implementations do compile to machine code at run time, but JavaScript does not "compile down to WebAss".


I'd rather use Rust than javascript 8 days a week


I wasted too much time trying to look if there was a way javascript date objects would report there being eight days in a week...


Well, good for you.


Let a thousand flowers bloom and all that, but come on. That particular flower is a freaking baobab already. I assume it's mostly for use outside of browsers.


> Highlights:

> No C/C++ or Rust required, just typed JavaScript.

That's not a flaw...!


It all depends which of all these ugly langages you are the least uncomfortable with. I hear they even use js for servers now. Rise and fall... lol


Honestly I thought you referring to Rust as an ugly language would send more replies your way.




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