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You are confusing inheritance of implementation with inheritance of interface. The consensus is to use inheritance of interfaces and use composition to impleme

You are confusing inheritance of implementation with inheritance of interface. The consensus is to use inheritance of interfaces and use composition to implement the interfaces. Hence my phrasing: "Inheritance is better achieved through composition".

jcelerier 8y ago
But you still use the OOP concept of inheritance, which is basically "indirect methods with function pointers". Beside, "interfaces" don't even exist as a syntaxic concept in many OOP languages, C++ being the most prominent one.
- spdionis 8y ago
  I think C++ is the only one that doesn't have interfaces.
  - maxxxxx 8y ago
    An abstract class with only abstract methods is essentially the same.
    - jcelerier 8y ago
      It's most certainly not: - you have to at least implement the destructor if you are going to use the abstract class across multiple DLLs - else, dynamic_cast won't work since each DLL may have its own type_info object for the abstract class - even if a method is marked abstract, it can still have a default implementation: https://gcc.godbolt.org/z/bAE7v6 https://gcc.godbolt.org/z/bAE7v6 though other prominent OO languages are slowly catching up with this ;)
- munchbunny 8y ago
  That's splitting hairs. Regardless of the syntax mechanism used to achieve it, inheritance of interfaces and inheritance of implementation are qualitatively different, in the sense that you can usually tell the difference regardless of language. Also, C++ has abstract classes with only pure virtual functions, which accomplish the same thing.
marcosdumay 8y ago
> The consensus is to use inheritance of interfaces and use composition to implement the interfaces. A consensus by the "maximization of boilerplate" rule. Inheritance is the most powerful tool available at the OOP land. It's the one thing that FP languages still didn't replace with enough added advantages to make the OOP stuff look like a toy. So if you are programming in OOP while avoiding inheritance, you would be certainly better in another paradigm. (And, of course, powerful tools are easy to misuse. That's no reason for forbidding them.)
- CMCDragonkai 8y ago
  Check out extensible records or Nix language fix pattern for its attribute sets.
- mercer 8y ago
  I'm not familiar enough to have a strong opinion on this, but the impression I get is that even the OOP camp (or thought leaders within those camps) seems to have abandoned inheritance in favor of composition. Assuming this is the case: why do you disagree and what do you think is the cause of this difference in opinion?

jcelerier 8y ago

But you still use the OOP concept of inheritance, which is basically "indirect methods with function pointers". Beside, "interfaces" don't even exist as a syntaxic concept in many OOP languages, C++ being the most prominent one.

spdionis 8y ago
I think C++ is the only one that doesn't have interfaces.
- maxxxxx 8y ago
  An abstract class with only abstract methods is essentially the same.
  - jcelerier 8y ago
    It's most certainly not: - you have to at least implement the destructor if you are going to use the abstract class across multiple DLLs - else, dynamic_cast won't work since each DLL may have its own type_info object for the abstract class - even if a method is marked abstract, it can still have a default implementation: https://gcc.godbolt.org/z/bAE7v6 https://gcc.godbolt.org/z/bAE7v6 though other prominent OO languages are slowly catching up with this ;)
munchbunny 8y ago
That's splitting hairs. Regardless of the syntax mechanism used to achieve it, inheritance of interfaces and inheritance of implementation are qualitatively different, in the sense that you can usually tell the difference regardless of language. Also, C++ has abstract classes with only pure virtual functions, which accomplish the same thing.

marcosdumay 8y ago

> The consensus is to use inheritance of interfaces and use composition to implement the interfaces. A consensus by the "maximization of boilerplate" rule. Inheritance is the most powerful tool available at the OOP land. It's the one thing that FP languages still didn't replace with enough added advantages to make the OOP stuff look like a toy. So if you are programming in OOP while avoiding inheritance, you would be certainly better in another paradigm. (And, of course, powerful tools are easy to misuse. That's no reason for forbidding them.)

CMCDragonkai 8y ago
Check out extensible records or Nix language fix pattern for its attribute sets.
mercer 8y ago
I'm not familiar enough to have a strong opinion on this, but the impression I get is that even the OOP camp (or thought leaders within those camps) seems to have abandoned inheritance in favor of composition. Assuming this is the case: why do you disagree and what do you think is the cause of this difference in opinion?