Architectural choices are interesting to talk about, but I think most people reading this won't have any context to compare against, me included. How does this compare to e.g. the architecture of V8? What benefits do these choices give when compared against other engines? Etc, reading through the list it's easy to nod along, but it's hard to actually have an intuition about whether these are good choices or not.

I recommend reading /Don’t Stop the BIBOP: Flexible and Efficient Storage Management for Dynamically Typed Languages/ (1994)[1]. "BIBOP" stands for "Big Bag of Pages."

1. https://legacy.cs.indiana.edu/~dyb/pubs/bibop.pdf

Isn't data oriented design driven by knowing what your data accesses look like? In your engine, you're building as if you're assuming that common data access will be linear access over objects of the same type. Why?

A short comparison to how V8 does these things:

1. All data in V8 is allocated into one of many heap parts: Usually new data goes into a nursery space, and if it does not get GC'd it moves to the old space. Relative position of data isn't really guaranteed at this point.

2. All heap references in V8 are true pointers or, if pointer compression is used, offsets from the heap base.

3. All objects in V8 include all the data needed for them to act as objects, and all of their data is stored in a single allocation (with the exception of properties, with some exceptions). The more specialised an object is, say an ArrayBuffer, Uint8Array, or a DataView, the bigger it has to be as the specialisation requires more data to be stored.

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.