[mananaysiempre]

Do you have any references you could give on this? I think I have a fair idea of all the object systems you listed (and a couple of others). Every time I read about ECS I feel like it should be explainable as some flavour of OOP much as you say here, and I could express something vaguely ECS-shaped in either Self/Io- or CLOS-style OOP, but that’s still a far cry from showing that ECS is such OOP.

In particular, keeping a single object’s state in several separate memory regions seems atypical (prototypes—or Self’s “traits objects”—are usually stateless even if the system doesn’t force them to be); and I can’t think of any way to map iteration over all objects that have parts of a specific kind, often mentioned in expositions of ECS, to a conventional OOP concept (looks relational if anything).