A WebAssembly compiler that fits in a tweet

Really interesting. I considered having a go at a RPN to WASM converter when I was making https://c50.fingswotidun.com/

I ended up converting the RPN style notation into a JavaScript string and creating a new function, which lets the JIT sort it out.

https://c50.fingswotidun.com/show/?code=xy!2*!2y!*6%2Bo2%2Fv...

which has the code

    xy!2*!2y!*6+o2/vy#!*:Cy#*+z#d!;*:ze!xy*4s*43/*e+*+

    ((round(z) * ((v * (1 - round(y))) + (clamp((( ((x*(2**((2 * (1 - y)) + 6))) ^ ((1 - ((1 - y) * 2))*(2**((2 * (1 - y)) + 6)))) /(2**((2 * (1 - y)) + 6))) / 2)) * round(y)))) + ((1 - round(z)) * ((1 - smoothStep(z)) + smoothStep((((x * y) * sin(4)) * (4 / 3))))))

Originally I created an interpreter for a code as a texture maker for code golfed javascripted games. https://github.com/Lerc/stackie

There's potential for a WASM implementation to be both smaller than the small version and Faster than the fast version.

Interesting how the obfuscated code is explained by slowly unobfuscating it step by step. This is the reverse of how obfuscated code is normally created: by starting with understandable code, and then slowly obfuscating it bit by bit (as I explained for this IOCCC submission [1]).

I say normally because one could also have a superoptimizer search for a minimal program that achieves some desired behaviour, and then one has to understand it by slowly unraveling the generated code.

[1] https://tromp.github.io/maze.html

Is this a Tweet or a Xit (zit)? ha.

This is cool though, i love these programs that exist in these constraints, like Dwitter does with the demoscene.

I’ve used reverse Polish notation as an interview question many times. It works well because if someone’s never seen it you can learn a lot about their basic understanding of algorithms. But if they are aware of how easy it is you can extend it forever by adding symbols, improving the algo they build, or doing something like this.

> if you take the time to understand what this code does, you’ll learn a surprising amount about WebAssembly!

It's a shame the article mostly teaches about codegolf tricks, and the actual wasm info is left to a single commented code block.

Nonetheless an interesting article about JavaScript quirks though!

post co-author here, let me know if you have any questions :)

This is really impressive. It is over 140 characters, but I guess "a tweet" can be any length now.

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