[arc619]

Unfortunately, while OOP promises code reuse, it usually makes it worse by introducing boundaries as static architecture.

OOP's core tenet of "speciating" processing via inheritance in the hope of sharing subprocesses does precisely the opposite; defining "is-a" relationships, by definition, excludes sharing similar processing in a different context, and subclassing only makes it worse by further increasing specialisation. So we have adapters, factories, dependency injection, and so on to cope with the coupling of data and code. A big enough OOP system inevitably converges towards "God objects" where all potential states are superimposed.

On top of this, OOP requires you to carefully consider ontological categories to group your processing in the guise of "organising" your solution. Sometimes this is harder than actually solving the problem, as this static architecture has to somehow be both flexible yet predict potential future requirements without being overengineered. That's necessary because the cost to change OOP architectures is proportional to the amount of it you have.

Of course, these days most people say not to use deep inheritance stacks. So, what is OOP left with? Organising code in classes? Sounds good in theory, but again this is another artificial constraint that bakes present and future assumptions into the code. A simple parsing rule like UFCS does the job better IMHO without imposing structural assumptions.

Data wants to be pure, and code should be able to act on this free-form data independently, not architecturally chained to it.

Separating code and data lets you take advantage of compositional patterns much more easily, whilst also reducing structural coupling and thus allowing design flexibility going forward.

That's not to say we should throw out typing - quite the opposite, typing is important for data integrity. You can have strong typing without coupled relationships.

Personally, I think that grouping code and data types together as a "thing" is the issue.

[belter]

> Data wants to be pure, and code should be able to act on this freeform data independently, not architecturally chained to it.

If behaviors are decoupled from the data they operate on, you risk a procedural programming style lacking the benefits of encapsulation. This can increase the risk of data corruption and reduce data integrity...

[arc619]

Behaviours don't have to be decoupled from the data they operate on. If I write a procedure that takes a particular data type as a parameter, it's a form of coupling.

However, there's no need to fuse data and code together as a single "unit" conceptually as OOP does, where you must have particular data structures to use particular behaviours.

For example, let's say I have a "movement" process that adds a velocity type to a position type. This process is one line of code. I can also use the same position type independently for, say, UI.

To do this in an OOP style, you end up with an "Entity" superclass that subclasses to "Positional" with X and Y, and another subclass for "Moves" with velocity data. These data types are now strongly coupled and everything that uses them must know about this hierarchy.

UI in this case would likely have a "UIElement" superclass and different subclass structures with different couplings. Now UI needs a separate type to represent the same position data. If you want a UI element to track your entity, you'd need adapter code to "convert" the position data to the right container to be used for UI. More code, more complexity, less code sharing.

Alternatively, maybe I could add position data to "Entity" and base UI from the "Positional" type.

Now throw in a "Render" class. Does that have its own position data? Does it inherit from "Entity", or "Positional"? So how do we share the code for rendering a graphic with "Entity" and "UIElement"?

Thus begins the inevitable march to God objects. You want a banana, you get a gorilla holding a banana and the entire jungle.

Meanwhile, I could have just written a render procedure that takes a position type and graphic type, used it in both scenarios, and moved on.

What do I gain by doing this? I've increased the complexity and made everything worse. Are you thinking about better hierarchies that could solve this particular issue? How can you future proof this for unexpected changes? This thinking process becomes a huge burden to make brittle code.

> you risk a procedural programming style lacking the benefits of encapsulation. This can increase the risk of data corruption and reduce data integrity...

You can use data encapsulation fine without taking on the mantle of OOP. I'm not sure why you think this would introduce data corruption/affect integrity.

There's plenty of compositional and/or functional patterns beyond OOP to use beyond procedural programming, but I'd hardly consider using procedural programming a "risk". Badly written code is bad regardless of the pattern you use.

That's not to say procedural programming is all you need, but at the end of the day, the computer only sees procedural code. Wrapping things in objects doesn't make the code better, just more baroque.

[kbolino]

OOP and especially post-OOP languages don't encourage the "Dog is-a Animal" type of inheritance that you describe. Sadly, education has not caught up to industry and so it is still often taught the wrong way. Composition-over-inheritance has been the dominant methodology of practical OOP for a long time, so much so that most post-OOP languages (Swift, Rust, Go, ...) have dropped inheritance entirely, while still preserving the other aspects of OOP, like encapsulation, polymorphism, and limited visibility.