No but seriously, I think both you and hackits make it clear that there's a lot of discussion over what OOP actually is. Which makes me curious: is there any research on the characteristics of OOP as it implemented in practice across languages? I'd be very interested in such research, because it seems to me that what is possible is often not practiced.
So, for example, Ruby might be all about 'message passing' as others, and all the tutorials and books I've read indicate, but in practice it might be indistinguishable from just calling methods on objects, or whatever distinguishes message passing from other OOP styles.
If no such research exists, how difficult would it be to scan codebases on Github to analyse this? I might be wrong, but it seems like this would be a worthwhile investigation: how do people actually use languages and what is 'OOP' or 'FP' actually like in codebases that claim to be one or the other.
Otherwise we're just getting tangled up in definitions and it's all a moo point.
Since 1960 till 2012, there are only 22 research papers that used empirical evidence with randomised cross over studies for language design.
As of which, Class inheritance had 4 randomized controlled experiments. With a collection of other studies. That is mostly of the information I have come across.
There is a research paper on Java that looked at how programmers use inheritance. It's a interesting read and its a good source. (https://researchspace.auckland.ac.nz/handle/2292/16840)
I think Google published another paper looking at development time and I believe the result was the biggest time consumer for programmer was dependencies not necessary the programming langue.
I agree. I would say a lot of things people do in OOP isn't really OOP it's just object modeling principles. You can apply the same principles in a different language without notions of objects/classes (javascript) comes to mind.
But yes, the number of variant perspectives on OOP make it a less descriptive term than would be ideal.