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Inheritance was invented as a performance hack (2021)

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Re: Inheritance was invented as a performance hack (2021)

#171

Post by bigstrat2003 »

wolvesechoes wrote: post #74
josephg wrote: post #36

Earlier quoted context omitted.

> The bottom line is, no one ever really used inheritance that much anyway If you think that, you have no idea how much horrible code is out there. Especially in enterprise land, where deadlines are set by people who get paid by the hour. I once worked on a java project which had a method - call a method - call a method - call a method and so on. Usually, the calls were via some abstract interface with a single imple…

"But there's a reason the crowd is moving against inheritance" Yes, in our fad-chasing industry the pendulum has moved in the other direction. Let's wait few years. There is nothing wrong with OOP, inheritance, FP, procedural, declarative or whatever. What is bad is religious dogma overtaking engineering work.

I definitely agree that the crusade against inheritance is just a fad and not based on good reasoning. Every time people say "inheritance is garbage that people only use because they learned it in school" it pains me because it's like, really? You can't imagine that it's because those people have thought about the options and concluded that inheritance is the best way to model the problem they are facing?

Contrary to what the hype of the 90s said, I don't think OOP is the ultimate programming technique which will obsolete all others. But I think that it's equally inaccurate to make wild claims about how OOP is useless garbage that only makes software worse. Yes, you can make an unholy mess of class structures, but you can do that with every programming language. The prejudice some people have against OOP is really unfounded.

Re: Inheritance was invented as a performance hack (2021)

#172

Post by neonsunset »

osigurdson wrote: post #165
josephg wrote: post #103

Earlier quoted context omitted.

I have a slightly different take: I think every new technology or idea is created because it solves some problems, but in the long run, we'll discover that it creates other problems. For example, transpiling javascript, C++ OO, actors, coroutines, docker, microkernels, and so on. When a new idea appears, we're much more aware of the benefits it brings. But we don't know the flaws yet. So we naively hope there are no…

Although Java/C# make you put functions in a class, you aren't compelled to think of a class as a "noun". Just call it "Utils" or something like that. A class is just a thing that you can put functions and / or data in. Use that however you want.

if anything, in C#, you can import the entire class as `using static MyFunctions;` and make such functions top-level. Well, usually you write an extension method instead since most functions act on some form of data but you get the idea.

(can also be imported globally with 'global using static ..' in a usings file)

Re: Inheritance was invented as a performance hack (2021)

#173

Post by karolinepauls »

osigurdson wrote: post #28
roenxi wrote: post #10

I'm not sold the evidence is there to show inheritance is a good idea - it basically says that constructors, data storage and interfaces need to be intertwined. That isn't a very powerful abstraction, because they don't need to be and there isn't an obvious advantage from doing so over picking up the concepts separately as required. And inheritance naturally suggests grouping interfaces into a tree in the way that se…

Yeah ya... everyone likes to go on and on about how inheritance is the root of all evil and if you just don't use it, everything will be fine. Sorry, it won't be fine. Your software will still be a mess unless it is small and written three times by the same person who knows what they are doing. The bottom line is, no one ever really used inheritance that much anyway (other than smart people trying to outsmart themsel…

> Your software will still be a mess

Your software will still be a mess but a mess you can work with. Not a horror beyond comprehension. We should aim for workable mess.

This is from experience working with both procedural/functional mess and OO mess.

Re: Inheritance was invented as a performance hack (2021)

#174

Post by jmull »

roenxi wrote: post #10

I'm not sold the evidence is there to show inheritance is a good idea - it basically says that constructors, data storage and interfaces need to be intertwined. That isn't a very powerful abstraction, because they don't need to be and there isn't an obvious advantage from doing so over picking up the concepts separately as required. And inheritance naturally suggests grouping interfaces into a tree in the way that se…

So... what even is the purpose of computer language abstractions?

To provide building blocks useful for the construction of programs.

There's a number of properties that are good for such building blocks... composability, flexibility, simplicity, comprehensibility, etc.

Naturally, these properties can conflict, so the goal would be to provide a minimal set of interoperable building blocks providing good coverage of the desirable properties, to allow the developer can choose the appropriate one for a give circumstance and to change when needed. E.g., they could choose to use a simple but less flexible block in one situation, or a more complicated or less performant block in another.

IMO, inheritance is a decent building block -- simple and easy to understand, though with somewhat limited applicability.

We can imagine improvements (particularly to implementation) but I think it got a bad rep mostly due to people not understanding its uses and limitations.

...I've got to say, though, if you aren't figuring out how to use the simple and easy tools, you're really not going to do better with more complicated and capable tools. People hate to admit it, but the best of us are still highly confused monkeys haphazardly banging away at keyboards, barely able to hold a few concepts in our heads at one time. Simple is good for us.

Re: Inheritance was invented as a performance hack (2021)

#175

Post by quietbritishjim »

osigurdson wrote: post #28
roenxi wrote: post #10

I'm not sold the evidence is there to show inheritance is a good idea - it basically says that constructors, data storage and interfaces need to be intertwined. That isn't a very powerful abstraction, because they don't need to be and there isn't an obvious advantage from doing so over picking up the concepts separately as required. And inheritance naturally suggests grouping interfaces into a tree in the way that se…

Yeah ya... everyone likes to go on and on about how inheritance is the root of all evil and if you just don't use it, everything will be fine. Sorry, it won't be fine. Your software will still be a mess unless it is small and written three times by the same person who knows what they are doing. The bottom line is, no one ever really used inheritance that much anyway (other than smart people trying to outsmart themsel…

> The bottom line is, no one ever really used inheritance that much anyway (other than smart people trying to outsmart themselves).

Inheritance is most definitely used in many popular C++ libraries, e.g., protobuf::Message [1] (which is base class to all user message classes and also has its own base class of MessageLite) or QWidget [2] (which sits in a large class hierarchy) or tinyxml2::XMLNode (base class to other node types). These are honestly the first three libraries that I thought of that have a non-trivial collection of classes in them. They're all stateful base classes by the way, not pure interfaces. And remember, I'm not trying to justify whether these are good or bad designs, just the make the observation that inheritance certainly is well used in practice.

(The fourth library I thought of with a reasonably complex collection of classes is Boost ASIO [4] which actually doesn't use inheritance. Instead it uses common interfaces to allow some compile-time polymorphism. Ironically, this is the only library in the list that I've been so unsatisfied with that I've written my own wrapper more than once for a little part of it: allowing auto-(re)connecting outbound and accepting incoming connections with the same interface. Guess what: I used inheritance!)

[1] https://protobuf.dev/reference/cpp/api-docs/google.protobuf....

[2] https://doc.qt.io/qt-6/qwidget.html

[3] https://leethomason.github.io/tinyxml2/classtinyxml2_1_1_x_m...

[4] https://www.boost.org/doc/libs/1_88_0/doc/html/boost_asio/re...

Re: Inheritance was invented as a performance hack (2021)

#176

Post by osigurdson »

josephg wrote: post #140
eru wrote: post #88

Earlier quoted context omitted.

And Rust's traits can sort-of inherit from each other.

I'm fine with trait inheritance. (If you want to call it that - its maybe better to describe it as trait preconditions.) I'm fine with it because trait inheritance doesn't increase code complexity in the same way C++ / Java class inheritance does. If you call foo.bar(), its usually pretty obvious which function is being called. And you only ever have to look in one place to see all the fields of a struct. In C++, its…

That is probably because you identify with the Rust tribe. Anything that Rust has is good while things in other languages have seem less good. This is fine, use the innate tribe affinity energy to get better at Rust.

Re: Inheritance was invented as a performance hack (2021)

#177

Post by WesolyKubeczek »

stickfigure wrote: post #166
josephg wrote: post #36

Earlier quoted context omitted.

> The bottom line is, no one ever really used inheritance that much anyway If you think that, you have no idea how much horrible code is out there. Especially in enterprise land, where deadlines are set by people who get paid by the hour. I once worked on a java project which had a method - call a method - call a method - call a method and so on. Usually, the calls were via some abstract interface with a single imple…

> The reason is that inheritance is almost always a bad idea in practice. It's just slightly too strong of a statement. I'm working in a very large Spring codebase right now, with a lot of horrible inheritance abuse (seriously, every component extended common hierarchy of classes that pulled in a ton of behavior). I suspect part of the reason is the Spring context got out of control, and the easiest way to reliably "…

There used to be times when language-level composition did not exist, so inheritance was practically all you had. There used to be ugly hacks to implement mix-ins, for example, in PHP (first versions of Symfony used them and did their best to make them not ugly, but they had to devote a whole chapter on how to do them right anyway). I suspect a lot of contention comes from those times — and from the fact that even when you can do better, many folks still have the muscle memory wired to "if inheritance is the only tool you have, everything looks like a subclass".

I like languages where I can have both, and where the language authors are not trying to preach at me.

Re: Inheritance was invented as a performance hack (2021)

#178

Post by nyrikki »

pjc50 wrote: post #120
pixelfarmer wrote: post #116

Earlier quoted context omitted.

I will tell you one example with inheritance: The Linux kernel.

How does that work in a language without inheritance? (yes, I guess it's the fake vtable of structure full of pointers)

Structure composition is a form of inheritance.

Re: Inheritance was invented as a performance hack (2021)

#179

Post by osigurdson »

josephg wrote: post #51
HdS84 wrote: post #43

Earlier quoted context omitted.

I don't think Inheritance is always bad - sometimes it's a useful tool. But it was definitely overused and composition, interfaces work much better for most problems. Inheritance really shines when you want to encapsulate behaviour behind a common interface and also provide a standard implementation. I.e: I once wrote a RN app which talked to ~10 vacuum robots. All of these robots behaved mostly the same, but each wa…

> I don't think Inheritance is always bad - sometimes it's a useful tool. I can only think of one or two instances where I've really been convinced that inheritance is the right tool. The only one that springs to mind is a View hierarchy in UI libraries. But even then, I notice React (& friends) have all moved away from this approach. Modern web development usually makes components be functions. (And yes, javascript…

The commenter used inheritance and thought it was fine. Probably not necessary to re-write in Rust just to be able to say that it doesn't use inheritance while being functionally the same thing.

Re: Inheritance was invented as a performance hack (2021)

#180

Post by williamdclt »

roenxi wrote: post #10

I'm not sold the evidence is there to show inheritance is a good idea - it basically says that constructors, data storage and interfaces need to be intertwined. That isn't a very powerful abstraction, because they don't need to be and there isn't an obvious advantage from doing so over picking up the concepts separately as required. And inheritance naturally suggests grouping interfaces into a tree in the way that se…

> Weird edge cases like HTTP over non-TCP protocols or rendering without screens start throwing spanners into a tree of assumptions that never needed to be made

yes, but that's true of other abstractions too. Whether you use inheritance or not, you usually don't know what abstractions you need until you need them: even if you were using composability rather than inheritance, chances are that you'd have encoded assumptions that HTTP goes over TCP until you need to handle the fact that actually you need higher-level abstractions there.

If you don't use inheritance, you switch to an interface (or a different interface) in your composition. If you did use inheritance, you stop doing so and start using composition. The latter is probably some more work but i don't think it's fundamentally very different.

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