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This seems to me like WebAssembly works basically like Java, but the bytecode can be compiled to from multiple languages. Is this correct?

Skinney 6y ago
It’s like Java bytecode in the sense that it’s a bytecode spec for a virtual machine, but otherwise quite different. Wasm doesn’t include a GC or support for OO out of the box. It doesn’t even have strings. That’s great for compiling languages like C++ or Rust though, but makes compiling higher order langues like python or java to it.
- emteycz 6y ago
  Yet. Support for these and more is coming: https://github.com/webassembly/proposals https://github.com/webassembly/proposals
thesuperbigfrog 6y ago
JVM bytecode can also be compiled from multiple languages: https://en.wikipedia.org/wiki/List_of_JVM_languages https://en.wikipedia.org/wiki/List_of_JVM_languages WASM needs to move beyond MVP state and get first-class support for DOM APIs in the browser and some kind of first-class OS-agnostic APIs for outside the browser. Until then I will be stuck with Java and J2cl/Closure (https://github.com/google/j2cl https://github.com/google/j2cl).
- emteycz 6y ago
  > some kind of first-class OS-agnostic APIs for outside the browser That's called WASI
throwaway189262 6y ago
It is like Java bytecode, but design geared more towards supporting C. Wasm in many ways is dumb. They could have easily adopted CLR or JVM bytecode. But no, the web is too "cool" for that. It's better to have a brand new VM that's slower and missing GC and a standard library.
- Shared404 6y ago
  Not an expert about anything related, but... > It's better to have a brand new VM that's slower and missing GC and a standard library. I can understand a desire to build something new and better suited for a particular goal. Didn't Java execution in the browser(loosely speaking) used to be a thing? I remember that causing security issues, and JVM/Java seems like a large enough thing that trying to mold it into something it isn't seems strange to me. As for the missing GC, I mostly work with Rust so that doesn't really bother me, although I could see how it would be an issue with other languages. Also, I believe WASI mentioned in the article is the standard library.
  - deleted 6y ago
    [deleted]
- gandalfgeek 6y ago
  The WASM instruction set is a tiny fraction of the size and complexity of the JVM and CLR instruction sets. One of WASM's primary design goals was to be able to prove safety and soundness properties for the language spec from the very beginning, and they've accomplished that [1]. Subjectively, I'd also argue that it is a much cleaner and more regular instruction set compared to JVM/CLR. Because it has a lower level of abstraction than JVM/CLR (which, for example, have a built-in notion of what an "object" is, and every other language that you compile to it must have its own semantics shoehorned into that), WASM was able to become a good target for C, C++, and Rust. The ultimate promise of WASM is that (given the right bindings) you can bring any C/C++/Rust codebase into the browser. E.g. see their demo of Doom running in the browser, utilizing WebGL bindings. [1] https://www.cl.cam.ac.uk/~caw77/papers/mechanising-and-verifying-the-webassembly-specification.pdf https://www.cl.cam.ac.uk/~caw77/papers/mechanising-and-verif..., explainer video https://youtu.be/zsPVbmEPTlA https://youtu.be/zsPVbmEPTlA
- imtringued 6y ago
  The web already adopted the JVM and Flash in the past and decided that it was a security disaster.
- deleted 6y ago
  [deleted]
afiori 6y ago
They were developed with different goals. WebAssembly is a stripped down version of asm.js that does not need to be compatible with Javascript semantics and is slightly closer to the hardware. In particular it shares with Javascript a strong security model.
- mega-tux 6y ago
  from website: WebAssembly (abbreviated Wasm) is a binary instruction format for a stack-based virtual machine. Wasm is designed as a portable compilation target for programming languages, enabling deployment on the web for client and server applications. asm.js an extraordinarily optimizable, low-level subset of JavaScript http://asmjs.org/ http://asmjs.org/ so, IMO WebAssembly is not a stripped down version of asm.js even if they sold it as that to js devs to foster adoption
  - afiori 6y ago
    Yes, you are correct. What I wanted to say is that webassembly is a continuation in that direction. At the time asm.js was ideated the alternative were browser plugins like NaCl, Flash, or Java. The problem with asm.js is that the requirement to be a subset of javascript meant that some optimizations were impossible. wasm is another step in that direction.

Skinney 6y ago

It’s like Java bytecode in the sense that it’s a bytecode spec for a virtual machine, but otherwise quite different. Wasm doesn’t include a GC or support for OO out of the box. It doesn’t even have strings. That’s great for compiling languages like C++ or Rust though, but makes compiling higher order langues like python or java to it.

emteycz 6y ago
Yet. Support for these and more is coming: https://github.com/webassembly/proposals https://github.com/webassembly/proposals

thesuperbigfrog 6y ago

JVM bytecode can also be compiled from multiple languages: https://en.wikipedia.org/wiki/List_of_JVM_languages https://en.wikipedia.org/wiki/List_of_JVM_languages WASM needs to move beyond MVP state and get first-class support for DOM APIs in the browser and some kind of first-class OS-agnostic APIs for outside the browser. Until then I will be stuck with Java and J2cl/Closure (https://github.com/google/j2cl https://github.com/google/j2cl).

emteycz 6y ago
> some kind of first-class OS-agnostic APIs for outside the browser That's called WASI

throwaway189262 6y ago

It is like Java bytecode, but design geared more towards supporting C. Wasm in many ways is dumb. They could have easily adopted CLR or JVM bytecode. But no, the web is too "cool" for that. It's better to have a brand new VM that's slower and missing GC and a standard library.

Shared404 6y ago
Not an expert about anything related, but... > It's better to have a brand new VM that's slower and missing GC and a standard library. I can understand a desire to build something new and better suited for a particular goal. Didn't Java execution in the browser(loosely speaking) used to be a thing? I remember that causing security issues, and JVM/Java seems like a large enough thing that trying to mold it into something it isn't seems strange to me. As for the missing GC, I mostly work with Rust so that doesn't really bother me, although I could see how it would be an issue with other languages. Also, I believe WASI mentioned in the article is the standard library.
- deleted 6y ago
  [deleted]
gandalfgeek 6y ago
The WASM instruction set is a tiny fraction of the size and complexity of the JVM and CLR instruction sets. One of WASM's primary design goals was to be able to prove safety and soundness properties for the language spec from the very beginning, and they've accomplished that [1]. Subjectively, I'd also argue that it is a much cleaner and more regular instruction set compared to JVM/CLR. Because it has a lower level of abstraction than JVM/CLR (which, for example, have a built-in notion of what an "object" is, and every other language that you compile to it must have its own semantics shoehorned into that), WASM was able to become a good target for C, C++, and Rust. The ultimate promise of WASM is that (given the right bindings) you can bring any C/C++/Rust codebase into the browser. E.g. see their demo of Doom running in the browser, utilizing WebGL bindings. [1] https://www.cl.cam.ac.uk/~caw77/papers/mechanising-and-verifying-the-webassembly-specification.pdf https://www.cl.cam.ac.uk/~caw77/papers/mechanising-and-verif..., explainer video https://youtu.be/zsPVbmEPTlA https://youtu.be/zsPVbmEPTlA
imtringued 6y ago
The web already adopted the JVM and Flash in the past and decided that it was a security disaster.
deleted 6y ago
[deleted]

afiori 6y ago

They were developed with different goals. WebAssembly is a stripped down version of asm.js that does not need to be compatible with Javascript semantics and is slightly closer to the hardware. In particular it shares with Javascript a strong security model.

mega-tux 6y ago
from website: WebAssembly (abbreviated Wasm) is a binary instruction format for a stack-based virtual machine. Wasm is designed as a portable compilation target for programming languages, enabling deployment on the web for client and server applications. asm.js an extraordinarily optimizable, low-level subset of JavaScript http://asmjs.org/ http://asmjs.org/ so, IMO WebAssembly is not a stripped down version of asm.js even if they sold it as that to js devs to foster adoption
- afiori 6y ago
  Yes, you are correct. What I wanted to say is that webassembly is a continuation in that direction. At the time asm.js was ideated the alternative were browser plugins like NaCl, Flash, or Java. The problem with asm.js is that the requirement to be a subset of javascript meant that some optimizations were impossible. wasm is another step in that direction.