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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)

#151

Post by colejohnson66 »

gpderetta wrote: post #119
kgeist wrote: post #95

Earlier quoted context omitted.

>no first-class support for them in the language. An interface is just a base class none of whose virtual functions have implementations. C++ has first class support for it. The only thing C++ lacks is the "interface" keyword.

The main reason (other than self-documentation) that some other languages separate interfaces form normal classes is that they only support multiple inheritance for interfaces. C++ doesn't have this restriction, so interfaces would add very little.

Because multiple inheritance causes the diamond problem. C# forces you to solve it by declaring one method as the "canonical" and the others as "explicit interface implementations" (only accessible if the variable/receiver is typed as that interface).

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

#152

Post by throw4847285 »

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 reason people don't have original opinions is because it isn't worth it. The stakes are extremely low. How one chooses to write code is ultimately a matter of personal preference.

The lower the stakes, the more dogmatic people become about their choices, because they know on some level it's a matter of taste and nothing more. Counterintuitively, it becomes even more tied to one's ego than the choices that actually have major consequences.

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

#153

Post by graealex »

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…

> And yes, javascript supports many kinds of inheritance

Funny you mention it, since JavaScript has absolutely no concept of contracts, which is one of the most important side-effects of inheritance. Especially not at compile time, but even at runtime you can compose objects willy-nilly, pass them anywhere, and the only way to test if they adhere to some kind of trait is calling a method and hoping for the best.

At least that had been the case till ES6 came around, but good luck finding anyone actually using classes in JavaScript. Mainly because it adds near-zero benefits, basically just the ability to overwrite method behavior without too much trickery.

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

#154

Post by [deleted] »

throw4847285 wrote: post #152
osigurdson wrote: post #28

Earlier quoted context omitted.

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 reason people don't have original opinions is because it isn't worth it. The stakes are extremely low. How one chooses to write code is ultimately a matter of personal preference. The lower the stakes, the more dogmatic people become about their choices, because they know on some level it's a matter of taste and nothing more. Counterintuitively, it becomes even more tied to one's ego than the choices that actuall…

[deleted]

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

#155

Post by chuckadams »

I think a lot of the arguments against inheritance come from C++'s peculiar implementation of it, which it clearly, ah, inherited from Simula. Slicing, ambiguous diamond inheritance, stuff like that are C++ problems, not inheritance problems. This isn't to say inheritance isn't problematic, but when you're making a properly substitutable sub-type of something, it's hard to beat.

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

#156

Post by sumtechguy »

josephg wrote: post #36
osigurdson wrote: post #28

Earlier quoted context omitted.

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 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…

Ah you have used spring/spring boot I see. That thing. It has humbled me. I didnt know you could do that much abstraction.

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

#157

Post by dgb23 »

ninetyninenine wrote: post #32
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…

It is a good idea because it's the most fundamental idea. You have two objects. A and B. How do you merge the two objects? A + B? The most straight forward way is inheritance. The idea is fundamental. The reason why it's not practical has more to do with human nature and the limitations of our capabilities in handling complexity then it has to do with the concept of inheritance itself. Literally think about it. How e…

> How else do you merge two structs if not using inheritance?

By merging them. Structs are product types. If you merge them, you get a bigger product type. You don't need inheritance (ADTs) for that.

The more useful point of inheritance is having shared commonality. But modern languages make it convenient to express that without using ADTs/inheritance.

TypeScript is fully structurally typed. If you combine a Foo and a Bar it is something new, but keeps being both a Foo and a Bar as well.

Go is structurally typed to a relatively high degree as well. You can embed types (including structs) into structs and only care about the individual parts in your functions. And you have composable and implicit interfaces.

Clojure has protocols and generally only cares about the things you use or define to use in functions. It allows you to do hierarchical keyword ontologies if you want, but I see it rarely used.

These languages and many others favor two fundamental building blocks: composition and signatures. The latter being either about data fields or function signatures. The neat part is these aren't entangled: You can use and talk about them separately.

How fundamental is inheritance if it can be fully replaced by simpler building blocks?

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

#158

Post by jollyllama »

josephg wrote: post #147
jollyllama wrote: post #139

Earlier quoted context omitted.

So if you've got a data object, defined in multiple places in a sprawling codebase, that you want to change, are you going to trust the LLM to find them all, and not miss a single one?

Why is your data object defined in multiple places in your codebase? And why aren't you using your IDE to change them all at once?

> Why is your data object defined in multiple places in your codebase?

Because that's the negation of my premise which you disagreed with: "Keeping to the DRY principle is also more valuable in the age of AI when briefer codebases use up fewer LLM tokens."

> And why aren't you using your IDE to change them all at once?

It sounds like you're assuming that they're all defined in the same way that you can catch them with a search.

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

#159

Post by osigurdson »

jollyllama wrote: post #141
josephg wrote: post #131

Earlier quoted context omitted.

> OOP is easily the lesser of the two evils; without it, you're doomed to violate DRY in ways that will make your project unmaintainable. Inheritance isn't the only way to avoid duplicating code. Composition works great - and it results in much more maintainable code. Rust, for example, doesn't have class based inheritance at all. And the principle of DRY is maintained in everything I've made in it. And everything I'…

I've experimented with GoLang and found the lack of inheritance to be crippling for cases when I want to set a pattern in the code that is to be easily used by other devs with minimal training and a shared definition of behavior. That said, I truly think some mix of inheritance and composition is probably best to avoid the situations we're describing.

It is possible, just look at all of the go packages out there. Also, maybe you don't need to wrap it up as tightly as you think. The "other devs" will use it wrong anyway.

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

#160

Post by Retric »

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…

Inheritance was oversold, but it can help remove a lot of boilerplate code. Early windows notoriously had hundreds of lines of code for a hello world program. Setting your own defaults and getting on with your day is great for dealing with a less refined API etc.

Complex inheritance trees can make sense in niche application for similar reasons.

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