This is a really cool package, thank you for sharing it. While I’m really not so keen on the whole OOP stuff, I do indeed think that type/field inheritance (like the example in this post) might be really nice for ABMs (my main field of research). So maybe this is something to try out in the future to see how well it works for my use case. 
While reading through the docs, I’ve stumbled upon something that frankly bugs me a bit though. As outlined here, regular type checks in Julia like
Snake <: Animal # false
just don’t work… Instead one needs to rely on specific methods like
issubclass(Snake, Animal) # true
which is kind of a no-go for me because it would require adaptation of “basic” Julia code when using the TyOOP.jl package. 