Many of the headaches associated with Rust come from an inability to reference from owned to owner. Affine types have much more impact on design than inheritance vs. composition.
If Inheritance is so bad, why does everyone use it?
11–20 of 389 posts
Re: If Inheritance is so bad, why does everyone use it?
#12IMHO inheritance works and only works for graphics related programming, e.g. GUI and games. Visual objects can be abstracted in the manner of inheritance.
Inheritance doesn't work well for games, that's why so many games take a component based approach like Unity, or full blown ECS.
Well, it does work well for the engine part of game engines, and graphics related code in particular as the GP says - it's just gameplay code where OO falls a bit flat.
Re: If Inheritance is so bad, why does everyone use it?
#13OOP is easy to understand and explain and it makes sense initially, plus a lot of people specialize in languages/frameworks that enforce it, so it becomes easy to get trapped in the OOP world. It also usually comes with DDD (which is a solution to a problem you shouldn't have had in the first place) which is a way to limit the damages of OOP into contextual areas.
I also think the blanket statement (OOP is bad) does not apply necessarily everywhere. A good mix of composability and a bit of inheritance where it makes sense is the best way imo.
Re: If Inheritance is so bad, why does everyone use it?
#14Some modern programming languages do not even have classes to inherit from. Instead they have concepts like traits and structs, which decouple structure and behavior.
Re: If Inheritance is so bad, why does everyone use it?
#15IMHO inheritance works and only works for graphics related programming, e.g. GUI and games. Visual objects can be abstracted in the manner of inheritance.
That's strange because I was about to comment the exact opposite. ECS is for games, inheritance is for almost everything else
Re: If Inheritance is so bad, why does everyone use it?
#16Nowadays I have rarely seen it if ever
Re: If Inheritance is so bad, why does everyone use it?
#17IMHO inheritance works and only works for graphics related programming, e.g. GUI and games. Visual objects can be abstracted in the manner of inheritance.
This has more or less been my experience too. Things like UI toolkits or game engine primitives are often solved nicely with inheritance.
I've been doing a lot with LeafletJS lately, and it has some light inheritance around its drawing primitives (things like boxes, circles and lines you draw on top of maps). It works well.
For 3D engines you still need to be quite careful with where you apply it though. It's possible to get into a huge mess if you use it too much.
Re: If Inheritance is so bad, why does everyone use it?
#18IMHO inheritance works and only works for graphics related programming, e.g. GUI and games. Visual objects can be abstracted in the manner of inheritance.
Especially in games, inheritance doesn't work all that great and had been replaced by composition via components a long time ago where each component implements one specific aspect or feature of a game object and can be (more or less) freely combined with other components.
Re: If Inheritance is so bad, why does everyone use it?
#19Smalltalk having a more or less revolutionary developer experience was likely quite important. A graphical interface to your system where you can traverse a tree and inspect _everything_, and more importantly, change it.
In Smalltalks as I know them, which is sporadically and shallowly, inheritance seems to be used as a factoring tool, when you break down functions into smaller functions there's a structure in which to place them with the implicit incentive to put them as high up as possible.
To me it seems to work pretty well, but it's also a rather weird environment where even classes themselves are objects.
In Java one can get around inheritance by using injection into an attribute in a wrapper class that extends or changes an object API. This leads to a similar decoupling as more functional composition, but you pay by having more objects swimming around in the VM during execution. Extending on the class level (i.e. in declarations of classes, interfaces, traits and the like) instead of the object level might have effects on performance and resource management.
Usually that likely doesn't matter, but it might. In Java-like languages I tend to use inheritance as a quick way to abstract over or extend functionality in a library class, I get the public methods 'for free' in my own class without having to write the wrappers myself. And that's usually where I stop, one level of inheritance, since Java isn't as inspectable and moldable as, say, Pharo, and doesn't give the same runtime ergonomics with large class/object trees.
Re: If Inheritance is so bad, why does everyone use it?
#20I work on a very large codebase. We use inheritance and composition. I totally agree that inheritance should be used carefully. However, there are times when composition requires a lot more code and downstream maintenance.
Let's stay I have a base class A. Let's say I have 70 classes that inherit from A.
These classes must serialize/deserialize from disk.
My choice here is that I can add a new data member to A and then update the read/write method in one place, or I add a new data member to all the classes that are derived from A, meaning that I get to update 70 classes. Seriously? Who would think this is a good idea? You'll have to write 70 times as much code... there will be times when that's definitely a very bad idea.
Maybe don't use inheritance. Then give every class its own "Name" data member like std::string c_nName. Every class can have its own function to set the name, or we could use an unencapsulated free function and do things like C. Except then the experts will say things like "well, now you're doing C with classes". Then you get a ticket that the user can enter bad names. You can then figure out some way to validate the names, right? That could be a free function, or maybe write some class called NameValidator. Except now the experts say you're writing C++ like Java. Too many classes, too few classes, too many objects, too few objects, too may free functions, too few free functions.
C++ expert of the month may say X, Y, Z, but look at Microsoft's APIs.
Inheritance is everywhere.
Look at any open source C++ project.
Inheritance is everywhere.
Does that mean that you should make something like:
A
--B : public A
----C : public B
------D : public C
--------E : public D
----------F : public E
Or this:
A B
\ /
C
Right tool for the job, yeah? I once read something in the C++ FAQ that said something like "Don't take advice from people who don't understand your business problems."