Porffor: A from-scratch experimental ahead-of-time JS engine

Post by zem » Tue, Jul 30, 2024, 10:50 PM UTC

mproud wrote: post #27

“Purple” in Welsh

Post by refulgentis » Tue, Jul 30, 2024, 10:53 PM UTC

obviouslynotme wrote: post #6

I have thought about doing this and I just can't get around the fact that you can't get much better performance in JS. The best you could probably do is transpile the JS into V8 C++ calls. The really cool optimizations come from compiling TypeScript, or something close to it. You could use types to get enormous gains. Anything without typing gets the default slow JS calls. Interfaces can get reduced to vtables or may…

Post by wdb » Tue, Jul 30, 2024, 10:58 PM UTC

syrusakbary wrote: post #8

It's awesome to see how more JS runtimes try to approach Wasm. This project reminds me to Static Hermes (the JS engine from Facebook to improve the speed of React Native projects on iOS and Android). I've spent a bit of time trying to review each, so hopefully this analysis will be useful for some readers. What are the main commonalities and differences between Static Hermes and Porffor? * They both aim for JS test26…

Post by canadahonk » Tue, Jul 30, 2024, 11:03 PM UTC

syrusakbary wrote: post #8

It's awesome to see how more JS runtimes try to approach Wasm. This project reminds me to Static Hermes (the JS engine from Facebook to improve the speed of React Native projects on iOS and Android). I've spent a bit of time trying to review each, so hopefully this analysis will be useful for some readers. What are the main commonalities and differences between Static Hermes and Porffor? * They both aim for JS test26…

Post by sixbrx » Tue, Jul 30, 2024, 11:10 PM UTC

wk_end wrote: post #32

munificent wrote: post #26

Earlier quoted context omitted.

I think the even bigger elephant in the room is that TypeScript's type system is unsound. You can have a function whose parameter type is annotated to be String and there's absolutely no guarantee that every call to that function will pass it a string. This isn't because of `any` either. The type system itself deliberately has holes in it. So any language that uses TypeScript type annotations to generate faster/small…

So - I know this in theory, but avoided mentioning it because I couldn’t immediately think of any persuasive examples (whereas subtype polymorphism is a core, widely used, wholly unrestricted property of the language) that didn’t involve casts or any/unknown or other things that people might make excuses for. Do you have any examples off the top of your head?

    type Fish = { swim: () => void };
    type Bird = { fly: () => void };
    type Human = { swim?: () => void; fly?: () => void };

    function move(animal: Fish | Bird | Human) {
      if ("swim" in animal) {
        // TSC infers wrongly here the presence of "swim" implies animal must be a Fish or Human
        onlyForFishAndHumans(animal); 
      } else {
        animal;
      }
    }

    function onlyForFishAndHumans(animal: Fish | Human) {
      if (animal.swim) {
        animal.swim(); // Error: attempt to call "not-callable".
      }
      // (receives bird which is not a Fish or Human)
    }

    const someObj = { fly: () => {}, swim: "not-callable" };
    const bird: Bird = someObj;

    move(bird);

    // runtime error: [ERR]: animal.swim is not a function