WebAssembly Stack Machine

The WA stack machine was added <i>late</i> in the game. Before that it was an AST but they got pushback from browser backend people and <i>pivoted</i> to a stack machine.<p><a href="https:&#x2F;&#x2F;github.com&#x2F;WebAssembly&#x2F;design&#x2F;issues&#x2F;755" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;WebAssembly&#x2F;design&#x2F;issues&#x2F;755</a><p>AST was a good idea and parsing as validation was excellent. Having a general stack machine makes validation much more difficult.<p>This is a bad decision (stacks vs AST or register) made for the wrong reason (code size). That&#x27;s a 1990s design assumption when memory was expensive and bandwidth was dear. Now memory is cheap; bandwidth is phenomenal; and latency is expensive.

If WASM runs on a stack machine, I wonder how hard it would be to map the instructions to JVM bytecodes? From the example in the document they look similar...<p>It would be interesting to be able to take code compiled with Emscripten for example and run it as part of JVM applications, similar to what NestedVM can do.

It makes me sad to see the AST go. I was thinking of writing my own WASM compiler just for fun, purely as an AST transformer.<p>Its funny how most of the WASM tools still use s-experssions as the text format. How does that even work, now that the AST is history?

I just wanted to say Im really excited about this project. I hope it will come together and make software universal as the web we have today (if I understand it right). Anyways, how can I contribute?

I believe that switching to a stack machine is short-sighted and a big mistake:<p>The AST format could open up new possibilities for software, some of which are observable in Lispy languages like Scheme (I won&#x27;t list them here). Instead, we&#x27;re looking at locking the software world back into this 1960&#x27;s model for another 50 years out of a misguided concern for optimization over power.<p>It&#x27;s like foregoing the arch because it&#x27;s more work to craft, and instead coming up with a REALLY efficient way to fit square blocks together. Congratulations, we can build better pyramids, but will never grasp the concept of a cathedral.<p>To really grasp my point, I BEG you all to watch the following two videos in full and think hard about what Alan Kay &amp; Douglass Crockford have to say about new ideas, building complex structures, and leaving something better for the next generation:<p><a href="https:&#x2F;&#x2F;youtu.be&#x2F;oKg1hTOQXoY" rel="nofollow">https:&#x2F;&#x2F;youtu.be&#x2F;oKg1hTOQXoY</a><p><a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=PSGEjv3Tqo0" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=PSGEjv3Tqo0</a><p>As Alan Kay states, what is simpler: something that&#x27;s easier to process, but for which the software written on top of it is massive; or one that takes a bit more overhead, but allows for powerful new ways to model software and reduce complexity?<p>I believe that an AST model is a major start in inventing &quot;the arch&quot; that&#x27;s been missing in software, and with something that will proliferate the whole web ... how short-sighted it would be to give that up in favor of &quot;optimizing&quot; the old thing.<p>Imagine if instead of JavaScript, the language of the web had been Java? Lambdas would not be mainstream; new ways of doing OOP would not be thought of; and all the amazing libraries that have been written because of the ad-hoc object modeling that JavaScript offers. Probably one of the messiest and inefficient languages ever written, yet one of the most powerful ever given. C&#x27;mon, let&#x27;s do it a step more by making it binary, homoiconic, and self-modifying.<p>Thanks.

I&#x27;d prefer it was an SSA representation, like SPIR-V in Vulkan, or LLVM IR. Missed opportunity IMO.

I&#x27;m confused about all of this - is WebAssembly related to the Google Native Client stuff they did and are now deprecating? Is there a write-up of how it works?