Rust Programming Language Rust Hungary Meetup, 23 Sep 2017

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From YouTube: Ingvar Stepanyan — Rust + WebAssembly = ❤️ (Rust Hungary Kickoff, 2017-09-23)

Description

WebAssembly is currently being actively developed on all sides - by browser vendors, language implementors, game engines developers and many others. What is it and why is it important? How can we use it to speed up our apps without going into scary lands of unsafe native languages? Let's take a deep breath and try to figure these things out together.

Presented by: Ingvar Stepanyan (@rreverser) — Rust + WebAssembly = ❤️
JS/D2D Developer, Rust/WebAssembly enthusiast, RustFest Kyiv Speaker | Cloudflare, London

Slides:

[Rust Hungary Meetup #1, 2017-09-23, Mozilla Hungary Community Space, Budapest]
https://www.meetup.com/Rust-Hungary-Meetup/events/242955063/

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And now we have you been diving bit deeper. Can you show me another bunch of Java developers here? Is there in LA working on the web like JavaScript about I'm? Sorry, alright, alright, there's there's a few people. You.

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This is why I hope you ask it because, because you don't see all right, so we have angler from from London all the way over here to John. We must talk to us about rust and grab assembly. So how do you put your roster into your web pages? So take it away? Thanks.

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I was going to more or less repeats attack from Ross Fez that I was being on web awesome VM by Qasim, GS & härtel works internally bugs and a ketone society will be known, so many system developers, but mostly JavaScript developers and I, had to change. But it looks like most of you are not have estate developer site. They paint your fence again.

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Than chocolate developers slightly take off.

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Ok guys so yeah I will still talk about who I bust me. I. Guess it's too late to change the topic of the talk and what exactly it is like white matters like. Why would you want to use it and how exactly would you use it to be spliced so, and my name is in war?

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I will get Claude systems engineer, partly-mostly I can see, but my background is mostly JavaScript I used to do that like full time so now, I'm trying to balance just not to lose ever since this happens in Java Golden's, it's like votes and to fast, but at the same time keeping it phone systems so yeah. Let's talk about the boss on the end, it will be like in three parts so as I like to call it Christmas Carol. If you're familiar easiest, you can story. Anyone for me. Is it.

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But we will go slightly out of order of the story. We will go first slightly to the future and we will meet binary-based. Oh the ghost of Christmas, yet to come.

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So binary ast is very recent development that historically in contests by Mozilla team, what it's and it's important to understand it to understand like what was a robust in bees or what it's not so binary St is currently stage. One proposal, there's like four stages in JavaScript for many proposals to the language is that one purpose, meaning it was accepted and it's being developed actually to be implemented in browsers. So the basic idea is that Mozilla, together with some Facebook people, looked into measure, websites and Raqqah said well.

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Obviously, I know chip in just few kilobytes of JavaScript anymore, let's see like 10 years ago, but all the major web sites have actually several megabytes of Jack's record page and it's not only like slow to execute like you can optimize mostly, but it's also kind of slow to even download it or parse like even before it started, accusing expended an enormous amount of time on just initializing, which kind of doesn't make any sense and, like modern browser engines, try to vote on that by actually doing stream in person as a content is being downloaded.

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But it's very hard to jump suit. Semantics, where, like some variable, can be before it's defined. You know and you need to move things around and you can't really get entire context. So the idea of this proposal is instead of having entire job switch back and we also like special unicode characters out of 40 variables and etc. You can just decode ever seen a convenient binary format where just encode the lecture ast as binary binary as as a three.

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We also know it's described in the beginning of the file and then like Jesse's. So basically, it's exactly the same JavaScript except it's structurally compressed into a proper data structure, and it's very fast course it's much easy to what we's, because you can just compress it and set aside pants and browser they do the rest on client side. So what this confirms? This experiment is that parsing time became like three times faster compared to just parsing, javascript lazy.

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Parsing time is like a fan, so first of all, it's like browsers are doing lazy parts and Wednesday I just skipped over top functions before actually executing them, as I tried to judge with what's in Turks, are but not actually ours and into the memory so that I'm good, reduce significantly as well and the GC besides good down as well, but most important is that you are spending much less time on like in charmazing good stuff.

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So just keep this in mind. While we go to the ghost of Christmas past, which is awesome checks, so a features were simply if you are doing some calculations, number crunching, so in JavaScript. Well, JavaScript is dynamic language. It's not very easy to do this kind of stuff quickly.

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Let's say you have some really stupid example: the season every CS keep a notch in numbers and it's very valuable negation for Watson for I know it because we are the Carson two times when we don't actually need that. But anyway, and it's a pretty good at trying to optimize it out to figure out all the types and so on, but still judge, which has its limitations. Because types can change in runtime you can replace function is another you can.

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You have only floats like no problem, integers and so on, and you know constantly, as it will search you can actually give hints to just with engineer advanced about what types you have, and so it's an typed language and this hints were formalize a single spec where it's still backwards compatible. It's just plain old JavaScript, so you can still run it all browsers, don't know some chairs, but new browsers can just parse it with completely separate asset and run in completely separate engine and not like JIT compiler, and it actually works.

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That's static language, just like C or after whatever else so to each operation. You have explicit type Marcos. So, in this case, it's just operation of binary or with you, which basically con which, by John systematic, just converts any float to integer but for oxygen, has enabled engine. It just hints it well. In most places we have only integers and it doesn't need to do any type, guessing Triton types whatever it can just go through this, compile it once statically and just reuse. This function.

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So yeah it's incompatible is backwards, compatibility honestly, but on modern engines it can work much much faster and this was developed a couple of years ago and it showed actually pretty good speed ups, because, instead of having entire huge jugs of engine working just to figure out like targets and get compiled as a function, it could be just a tiny converter to directly to machine code from this subset and even for sister.

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If you simple Fibonacci example, you can see that it gives like for it speed ups, just because engine knows all the tax and it's all taken apart already and the fun part needs worked even on more complicated amis, obviously than just some simple function. So this I don't know if Jesus is down by Mozilla couple of years ago, was reported entire Unreal Engine to ask Jess by just cross compile. It is a subset of JavaScript from C and C++, and what which is mostly close to negative, and he couldn't see any legs over teller.

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What couldn't be achievable? It's just right, we're just it may be it killed them. Well, in this case, I could just cross, compile the same code like without any extra effort, and it just worked so what awesomely ease? Oh, the ghost of Christmas present as I like to call it. It's combination of previous two ideas, basically or more problem binary jet, was derived from idea for passing where browser engine vendors decided that make yes is subset of jobs. Reports in that was compatible advice, but we have all these extra type annotations.

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Now the just becomes even bigger and when you just compiled like huge game engine. Well, it's not very nice to wait while you download, like twenty or fifty megabytes of JavaScript, just to stop showing something. So they decided to develop a partner format is that that would represent all this native operations in a cross-platform format that they could just convert to machine code, research it compile it, but it would be much smaller sense of original child, strict, always see whatever.

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So, basically, it's a common cross-platform binary representation of native code, whereas native code is usually like specific roles, CPU for operating system and so on and awesome just Maps directly to web awesomely. So all these type annotations get converted to prompt instructions where they just operate these technologies at each point of time and.

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Of the right section.

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So this is just a text representation for robots. It's used, like put your body and just I've decided what's going on inside, because country tonight.

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He is they just like integers and for, whereas on the Ducks format, they decided, which is nice, because.

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And easy to read and so on, but at least you get nice instructions instead of all the ugly type annotations in profit across the code, so I would Fibonacci search in robust on the tax form. What would look like this? This is a greeting and.

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You can see actually what's happened.

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Like we're defined function whose actual parameters we.

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Are censored Eve and we.

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Exclusively have types on every single operand lake, the comparison to second to be integers, and then we have inconel like instruction what happens if it's true and so on? So it's pretty much like this original example. It's relatively reasonable, but the main point is that it's very well compressible, because you have only very small subset of instructions that you need to care about, so whatever passionately is its it cuz. It's also like this text format for humans trying to fill table.

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As I said, this stack machine is binary format where all the values I just put on stack and you can come back to support if you are familiar, is like polish notation. Fortunately like it's very similar, and it has several compare like kind of to compression layers on top of the binary format, one of which being still in development, is actual compression, where you can have own functions for sections of your binary. That tells how to read the binary.

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So you can tell me so you can compress the code with like your own algorithms and tell us how you want to decompress it back before it's even compiled to machine code and then, as.

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A compression that.

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Is just using gzip or broadly whatever? Is it available poverty in browser, because why not and.

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So you have to be clear like if you didn't need ask Jeff before. If he didn't want to run your native code in browse, we probably don't need web part simply as well, because it's exactly the same thing, it reads is the same engine it just a little smaller mutations because it adds like mo low-level operations to the game. But if you do want to do some heavy calculations in prod on objects, it's probably nothing! Okay. So how do we use it on a page? It's usually done like this.

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You just fetch something like compile, doesn't be your requested as a binary buffer. You say rebuttal instantiate its internal operation by passing this the compiled binary. It compiles it to native code in background and when it finishes, you can say: okay well call this function possum.

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So the button is just like at modules that is complimentary to each other script, but you can pass it like own inputs and you can give NSS it it explores. They simply use it. If you don't want to really do some transformations, but it's not really recommended because then it will block your UI or server side while call the code is compiler, which is usually not the things if you want, but at least it's much easier to use for small experiments where you can just instantiate separate instances concurrently.

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So how can we use it? Because, obviously you you don't want to write this like hand, so we're passing the text board. You know you can, and there are some tutorials that show cathartic, it's not the most convenient to do. You usually want to just cross, compile suppose that you already have another language and that's where I'm tripping comes to play. So what is Krypton is eats at projects that evolved from C compiler called C.

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Mon Sealand is like LLVM based compiler developed by Apple, which basically takes a C C++ converts it to internal control flow control, flow graph representation.

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Then converge to inter allows the embed code. It's common for any event, which is at infinity on top of Olivia like automatically produces native objects and is actual native executables that you can draw so.

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Or any other comparison, you know what encrypting did they just put silent but replace some small parts of it. So, instead of the girls from native objects and made it exactly table, it just generates John script over by something instead, so initially it was just generating passengers out of native food.

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Now it's useful, possibly, which is essentially the same thing, just different representation for so it was an easy design reject and now as convenient students or us is also based on a little VMs Florio said Russ just takes bastard, it collects to reduce native objects and a to exhibit. So, even though I'm scripting is a fork of C compiler, what we can do to use Russ to compile to the bus into a desk chairs, we can just skip some parts of it when we just seen them together.

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We see that we can go directly from a little bit code to just to pass. Only is the last step of X cryptic and such a thing. What Russ did when it added native support for escape the targets? Basically, one gospel, this element with called out of its own passcode. It just sends it to unscripted and executing days care of Kentucky to get to just read awasum, because it's much easier entering the 90s at the same logic, compiler.

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Yes, we kissing, so how can you recommend our fashion rocks? Well, mass index is the expressive summertime from Jessica content, simple since first four seconds, another topic, so actions speak much like it looks in JavaScript, except in trust. You can recommends return. It will automatically returns in Australia at the Kamikaze function. Assume is that you don't have semicolon and you can just pull one if I meant to keep ten installed in your system, I can just call or Astley's Rossy target. Wasn't cyclic you on our web scripting.

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That's like a special triple sec chance to come back to.

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And well, first problem is that it says main function is not found because by default any a jumpsuit, the robot, so the output is expected to be just executive. If you want to explore some function, we need to trick it into thinking sit well, it's exactly table, but it has some functions. So first thing we do is just at empty may.

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Well, that's not where our journey edits, when we try to compile that each kind of compiles, but it doesn't really work when you try to actually just go to know them likewise, is dangerous. You can see the play it cleans them stripped and what your object and immediately that's it. This is not fun. Obviously, if you want to use actually something out of this option before exit there isn't possibility, simple is a trust by default. Just in sets an optional exit instruction into your mind, even though your mind is empty traps.

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It into another internal function, so actually exits. Your app is your exit code and tracks all the errors that happen inside everything, and there are several ways to work around it to keep it running, but most easiest is to use executing function. That is exactly for that. So she doesn't have the bomb, because in C you can compile exactly stable. Even if, like you, don't affect many well in rust, you need to take it to it a bit so.

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We do here, we define an example where the inputs, a function called inscription exit, asleep runtime, which the rust looks like any other input from like C libraries or anything else and in mind. You use it in Excel flow because any extents in rust consider access, because fast can attract, what's happening inside of it, and this will at least keep it running, which is nice.

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But if you try to call the function and in it you can use it by calling the C code with the function and define it because I'm skip the policy, doesn't sound like what types you want to pass inside of it. It says connected call another function, CD, because we missed one middle send our country, if not action expected, is just internet.

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So what we need to do is and the same directives as we use to export our function to see and Russ will take care of the rest to tell exclusion to actually expect so we met pump xn, which speckle says it's public function and also its exports out of our binary, and then we say no man goo just so the trust knows well.

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This country should preserve its name, because we want to actually find it later somewhere and call it by name and not just address after this, when we compounded, we can just use it directly from node by Parsons, name, arguments and argument types, and we can actually see the second correct, which is also nice in what one little so that you don't seem like when you're excited with Sierra. You know what is it? What if I just call the function directly?

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Not now we have Type R is it well. Just has lungs lipstick trace, which basically ends up showing that said function doesn't exist, which is weird because it just did, and here comes the favorite property of JavaScript.

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All the things.

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Are happening asynchronously, usually.

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Because say it is slope to just block, say July or satisfied because John shape the single psychic. Usually you don't want to wait. Well, something small happens, including reversing the complexion, as I said, like it's happening essentially and executing these compiles, but it doesn't directly tell you that open it finishes. It doesn't great for separation. So what you can do is when you input the module you can subscribe to special event like on runtime initialized and inside of it.

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You can actually be sure that your model was probably compiled by now, and you can actually use multi functions that you exposed.

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After this, everything should walk, so is it fast? That's some reason to do this at all. So is very simple right back where we just defines a Fibonacci function from the first slide, we're just up here, just leaping from the answer brass compiled one. We consider two we're passing the one is actually slightly slower. The reason for that being very simple. It's very easy to forget. Asian flex, to rust after we yeah OH II, actually compiled and gives some nice benefits, so lovely fell almost four times.

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Speed up, just like we saw is awesome yet because I said like it's basically the same engine, and as in small sense, it we can squeeze out unit is that we had right now call in sick all these parameter types and every sin every time, which is not very nice, because every time it has to actually parse the string names of also types and actually converts on its own. Instead, you can tell them to just rub the function once and then just call these parameters anyway, instead of passing single time.

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This doesn't give that compressor, speed up but and as a zero to three milliseconds, and this number grows like SS. You try to throw Fibonacci number now debugging. This stuff is easy. Ish, because when you try to look inside of it correctly were passing the unlike awesome.js well, first of all, it's not necessary gable assessment, JavaScript anymore and second, with dozens of our source maps where, in your JavaScript, depending actually have source maps that show you its original source as you're, stepping straight and instantly.

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You are getting some some exists where you can actually go through and.

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So you actually need to know why.

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Just slightly differently formatted one.

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Lessons that we can see.

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Is rough managed to avoid the recursion completely so.

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Instead of proportion.

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You know just invited ever seem to do well, because, if you get, it doesn't actually need to the cost anyway, and just all the variables this and also not sensitive, that is static language itself, just using interpreting every street you can just figure out said it doesn't need to do exertion and that's one of the reason of for its speed up CP idiot, not only questions that is natural talents like okay, so we can call into web us in the end, there's a number crunching, but how do we call out of it if you want to do something in the middle?

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So this is nice input object in Robeson Institute, where you see already, we can pass any inputs if you are actually writing robust and be yourself, but the phone is that currently it's not exposed to rust or as far as I know UNC.

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You can't tell what you want from JavaScript side instead of scripting uses it for its own goals. Internally, like for lots of goals, all these functions are implemented on JavaScript side and, if scripting periodically calls out to them when it wants to do something useful asking about from the branch but actually go to the network or create threads using web office or from Avellino. Whatever else is not available inside.

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So, let's see found seawaters work surrounded, even though I promise not to come in to see we, let that probably the only way so in C.

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One of the simplest way to call some JavaScript is a macro provided by Emscripten, where you can just say a 10-person, and we said if it would end adjust it and it will do the recipe so what it actually like how it is defined. Well, when we dig inside of the headers, we can find that this marker guess call some magic function where it's 25 0 code and pass all the arguments.

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So the code is literally a string that is moved out of our binary later during compilation phase and absolutely just does two things, and so we can just read upon this function on the raw side. If we want to do exactly the same, we define a 15,000 Const with code, been just bite pointer, because restraints and see strings are slightly different and.

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We can call it directly with our string, who is one small cabinet, because we are calling in to see it's very easy to forget to explicitly at sea or but because roster centers as well boss and what. But it looks quite ugly.

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One little clips that we usually do into a stairwell, then Anthony see just drop it into some nice macro when you can find it inside of marker. Just like and script in, does it's not likely anymore and you can just drink if I inside let zero about Custer all the types and unsafe. So the user doesn't even know that it's actually unsafe to do that, and then you can just call it a block which looks really nice.

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You can just embed Jump Street directly, it's like if you're asked anywhere I need to just walked into me with it, and you get nice pop-ups, because because in Lawson you can just pop up the hell out to see user, that's pretty much it any questions.

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Okay, so the question is: why do we with us in the mind we just allow them the wrong diesel beam IR? Is it does almost the same thing exactly the still has to be specific operations first and second, it's too unsafe. It's like very low level thing, while the bottom ve, like one of the goals, is that you can't run outside code on the web. You can't just go out of the boundaries and etc. So you still need some layer in between two surfaces. That would add, say: media checks.

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Pretty much, but it's just allows you to avoid almost all the instructions that are unsafe, buzzer in nature like also low level memory operations and so on. So you can still compiled so you can see compared to a low V M s, compilation, step to worry about, like.

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