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cyber_kinetistyesterday at 3:50 AM3 repliesview on HN

I think the main issue is that Bun relies heavily on existing C++ libraries like JavascriptCore, and these require RAII and ref-counting semantics from C++ that are closer to Rust than Zig.

You could write a JS engine with Zig-like idioms (arena allocation, static initialization), but that would require re-writing the whole JS engine from the ground-up (though I would definitely be interested in it if someone actually tries to do it!)


Replies

kllrnohjyesterday at 5:59 AM

> You could write a JS engine with Zig-like idioms (arena allocation, static initialization)

Arena allocators & static initializers are not novel. You'll find them in high performance C++ projects as well, such as LLVM or JavaScriptCore. But arena allocators have the quite significant limitation that they only help when everything being allocated in them have approximately the same lifetime. So they don't help when you need to allocate memory to provide the native implementation of a JavaScript object, for example (eg, FFI).

vintermannyesterday at 10:12 AM

> You could write a JS engine with Zig-like idioms (arena allocation, static initialization)

Could you actually? That seems like a bad fit for a JS engine to me. Predictable memory requirements are great when you can have them, perhaps you can avoid complexity then, but for a JS engine?

ttfleeyesterday at 3:59 AM

Why not using Swift?

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