wisp

I also based my Zig Lisp interpreter on delimited continuations and had a great time implementing async, resumable exceptions, dynamically scoped variables, and so on, on top of that. The single-stepping continuation-shuffling evaluation paradigm also made it really easy to expose evaluations as objects and stepping as a function. A simple form like (set! e (run (+ 1 1)) stores an evaluation—whose continuation and lexical environment can both be inspected and serialized—and (step! e) does a single evaluation step. This lets you implement not just yield-based cooperative concurrency in "user space" but something like green threads with a preemptive scheduler. Here you can see how the delimited continuation control allows binding to JavaScript's Promise API in a way that lets you treat promises as blocking computations: https://gi

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

This is would be a great project to provide a mature Lisp that developers could use to target WebAssembly. Guile Scheme is an amazing Lisp to utilize for this purpose. Here are some other Lisp-to-Wasm type projects from my brief search. -The Wisp project to compile Lisp-to-Wasm: https://github.com/mbrock/wisp -Chaitin's Lisp- This is a WebAssembly port of Gregory Chaitin's minimal Lisp interpreter: http://weitz.de/chaitin/ -HN post: Common Lisp running natively over WebAssembly: https://news.ycombinator.com/item?id=31590819 Great idea!