Show HN: Nova JavaScript Engine

This is a great idea! I had thought about doing this with a lisp interpreter. I had identified a few key advantages:

- homogenous allocation means no alignment gaps - linear access win in garbage collection - indices smaller than pointers - type discriminated index can save some size

I haven’t verified whether those actually work out in the details. I’ll read your blog article.

Don’t bother with these comments immediately comparing it to V8 (a multi billion dollar venture). I don’t know how many creative projects they’ve done before.

You may be be interested in looking at Fabrice Bellard’s JS engine for ideas.

I actually made a Lisp interpreter in Zig a couple of years ago that has each object type in a separate heap array. In fact each field of each object type has its own array: every CDR is in one contiguous array. This was mostly for fun and to experiment with data-driven techniques using Zig metaprogramming. The code turned out relatively clean and simple.

https://github.com/mbrock/wisp

GC is stop&copy which as a side effect compacts each of those arrays and improves locality. I think most lists should end up having their CDRs next to each other in memory making iteration very cache friendly. But I didn't verify any performance qualities, beyond making it efficient enough for basic use.

It also has delimited continuation control, compiles to WebAssembly, and hooks promises into the continuation system, among some other pretty cool features!