I’m currently working on Tiny [0], a small statically typed programming languages which is even more minimal than Wren.
As such, the "array" type is just an opaque type exposed via the C binding API. Given that there are no generics at the moment, this array API works with "any" values (similar to "any" in e.g. TypeScript).
BTW: I think I found a typo: "MATCH2("+=", PERCENTEQUAL);" — should be "%=" ??