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If Inheritance is so bad, why does everyone use it?

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Re: If Inheritance is so bad, why does everyone use it?

#171

Post by BatFastard »

arcticbull wrote: post #136

Boring answer: Same reason we do a lot of stupid things, haha. “If C is so unsafe and C++ is so unwieldy why does anyone use them?” Because that’s what they learned, or because that's how the codebase is structured when you get there. When all you have is a bike you’re going to ride that shit everywhere. You rarely if ever get the chance to start from scratch at work (where most code is written) and your job is to fo…

Main reason I use c++ is because it has the most mature libraries.

I gave Rust a try, and lots of nice things about it. But many of its libraries are not very mature.

Re: If Inheritance is so bad, why does everyone use it?

#172

Post by photonthug »

nertirs wrote: post #46

I only tend to see inheritance in engines and libraries, where it makes sense to create more generic, reusable and composable code, since most of the functionality in these is defined by technical people. It makes no sense to use inheritance in the business layer, because a single feature request can make a lot of the carefully crafted abstractions obsolete.

I've never seen it put quite like this, but it feels right and is refreshingly concrete. Trust the abstractions you can actually design/control for, treat all the other ones as suspect. One still needs the wisdom to tell the difference, but at least focusing on "feature request" focuses the mind. This is at least simple even if it is not "easy".

An argument against OOP where you first need to define/explain differences between composition/inheritance, Liskov Sub, compare and contrast with traits, etc is not really that effective when trying to mentor junior folks. If they understood or were interested in such things then they probably wouldn't need such guidance.

Re: If Inheritance is so bad, why does everyone use it?

#173

Post by michaelrpeskin »

bluetomcat wrote: post #69
captainmuon wrote: post #39

I feel people don't understand what inheritance and (object orientation in general) is useful for, misuse it, and then it gets a bad reputation. It's not about making nice hierarchies of Cars, Fruits, and Ovals. For me the main point is (runtime) polymorphism. E.g. you have a function that takes a general type, and you can pass multiple specific types and it will do the right thing. And if you want to avoid huge if-e…

Polymorphism is doable in plain old C with lookup tables and function pointers. If that is the only benefit, what is the point of creating a language where everything is an object?

> what is the point of creating a language where everything is an object?

I think that's the ultimate culprit in everyone hating inheritance. If it weren't for Java, I think we'd all have a healthier view of OO in general.

I learned OO with C++ (pre C++-11), and now I work at a Java shop, but I'm luck that I get to write R&D code in whatever I need to, and I spend most of my time in Python.

In C++ and Python, you get to pick the best tool for the job. If I just need a simple function, I use it. If I need run-time polymorphism, I can use it. If I need duck-typing I can do it (in Python).

Without the need for strict rules (always/never do inheritance) I can pick what makes the best (fastest? most readable? most maintainable? most extensible? - It depends on context) code for the job.

Related to TFA, I rarely use inheritance because it doesn't make sense (unless you shoehorn it in like everyone in the threat is complaining about). But in the cases where it really does work (there really is a "is a" relation), then it does make life easier and it is the right thing.

Context matters, and human judgement and experience is often better than rules.

Re: If Inheritance is so bad, why does everyone use it?

#174

Post by eyelidlessness »

layer8 wrote: post #146
EPWN3D wrote: post #80

It seems like protocols solve 90% of the problems that inheritance does, but with 10% of the headaches. Instead of trying to ensure that two types can both be passed to a function that only knows about the parent type, just have a parameter that says "Whatever's passed has to conform to this, I don't care what it is otherwise."

“Protocols” is Apple-specific (or Objective-C/Swift-specific) terminology. They correspond to types 1 and 2 of inheritance that TFA mentions.

Protocols as a term have other prior art. Which shouldn’t be surprising because a protocol is also descriptive of interface boundaries between software products (such as, but not limited to, network protocols).

Re: If Inheritance is so bad, why does everyone use it?

#175

Post by VirusNewbie »

layer8 wrote: post #142
VirusNewbie wrote: post #125

Earlier quoted context omitted.

>For me the main point is (runtime) polymorphism. But you don't actually care about runtime polymorphism here. You care about polymorphic behavior, which can be implemented in a much more composable way with parametric polymorphism.

You can’t build a dynamic list of objects implementing the same interface in different ways with parametric polymorphism. As another example, the Unix file interface ( open() , read() , write() , flush() , close() ) etc. is an example of runtime polymorphism, where the file descriptors identify objects with different implementations (depending on whether it’s a regular file, a directory, a pipe, a symbolic link, a de…

>You can’t build a dynamic list of objects implementing the same interface in different ways with parametric polymorphism.

Yes you can. that's the whole point of type classes.

Re: If Inheritance is so bad, why does everyone use it?

#176

Post by cjpearson »

seanwilson wrote: post #84

Nobody calls it this, but cascading styles in CSS is just like inheritance and I think should be avoided for all the same reasons. I feel it's a big part of why CSS at scale becomes unmaintainable. There isn't even a built-in way to compose two classes together if you want to avoid cascading/inheritance. It looks like composition over inheritance has caught on as the better default in other languages, but in the CSS…

CSS does actually call it inheritance[0], but it's commonly mixed up with the cascade. Inheritance applies to certain properties, so that when they are not specified on an element, an element inherits the value of the parent.

The cascade[1] determines how rules from multiple sources are merged.

[0]: https://developer.mozilla.org/en-US/docs/Web/CSS/Inheritance [1]: https://developer.mozilla.org/en-US/docs/Web/CSS/Cascade

Re: If Inheritance is so bad, why does everyone use it?

#177

Post by kaba0 »

mrkeen wrote: post #73
captainmuon wrote: post #39

I feel people don't understand what inheritance and (object orientation in general) is useful for, misuse it, and then it gets a bad reputation. It's not about making nice hierarchies of Cars, Fruits, and Ovals. For me the main point is (runtime) polymorphism. E.g. you have a function that takes a general type, and you can pass multiple specific types and it will do the right thing. And if you want to avoid huge if-e…

> For me the main point is (runtime) polymorphism. E.g. you have a function that takes a general type, and you can pass multiple specific types and it will do the right thing. The runtime part is what I dislike. If I have a fruit which is an apple or a banana, I can't pass that to a method expecting an apple or banana. It can only be passed as a fruit. > And if you want to avoid huge if-else statements, you should pu…

> The runtime part is what I dislike. If I have a fruit which is an apple or a banana, I can't pass that to a method expecting an apple or banana. It can only be passed as a fruit.

Heh? An apple is a fruit, you can pass it to any place expecting the former. Like, this is Liskov’s substitution’s one half.

With generics, you can be even more specific (co/in/contra-variance).

Re: If Inheritance is so bad, why does everyone use it?

#178

Post by gorjusborg »

gentleman11 wrote: post #126
parpfish wrote: post #86

Earlier quoted context omitted.

if i were writing an intro to programming book, i would introduce OO as a means of building encapsulation. i'd only get into inheritance in later chapters.

You can have encapsulation without oop. Polymorphism is the real benefit of oop imho

> Polymorphism is the real benefit of oop imho

It's pretty much the definition of OOP.

The core feature of OOP is just bundling functions with the state it processes.

When you bundle state and functions together, you can't predict what calling the function will do without knowing both the code and state.

You can say its 'the real benefit', I guess, but that feels like circular reasoning. Its pretty much the definition of what OOP is, so calling it a benefit feels weird.

Unfortunately, designing systems as a collection of distributed state machines tends to become maintenance nightmare. Functions and data being separated tends to make code better, even when working in so-called 'OOP' languages.

Re: If Inheritance is so bad, why does everyone use it?

#179

Post by HumblyTossed »

d_burfoot wrote: post #122

It seems like there's a huge industry of people critiquing Java and OOP but misdiagnosing the problems as technical rather than sociological. The immense pain and suffering that is related to Java and its ecosystem is because of the terrible organizational conditions that tend to co-occur with usage of Java. Big slow companies, long boring meetings, arguments about design patterns, "architects" who haven't written co…

Yeah, there's nothing wrong with Java the language. Java the community is what sucks. You had a few bloggers get popular and then a bunch of devs trying to make names for themselves would ape what they said, compound a few years and you have the mess people like to complain about.

Happens with a lot of language communities. C#, good grief, not much better than Java. Go(lang) community's favorite two words are "idiomatic Go". You can't read any post without seeing those two words. Go has like what, seven keywords. Let it go, man.

Re: If Inheritance is so bad, why does everyone use it?

#180

Post by josephg »

ldjkfkdsjnv wrote: post #131
d_burfoot wrote: post #122

It seems like there's a huge industry of people critiquing Java and OOP but misdiagnosing the problems as technical rather than sociological. The immense pain and suffering that is related to Java and its ecosystem is because of the terrible organizational conditions that tend to co-occur with usage of Java. Big slow companies, long boring meetings, arguments about design patterns, "architects" who haven't written co…

Java complexity is also an artifact of Java being used in large complex systems. People are really complaining about how hard programming is. There are many types of large scale systems where I would only code it using the JVM, everything else is a nightmare. Big tech companies largely feel the same

> There are many types of large scale systems where I would only code it using the JVM, everything else is a nightmare.

I’ve seen more than one lifetime’s worth of nightmare code written in Java. I agree with the GP commenter - I don’t think the problem is Java (the language) so much as the culture surrounding it. The Java programmers I’ve worked with (all smart people) seem addicted to solving all problems my writing more Java. More interfaces (most of which just have a single implementor). More classes. More files. More abstractions. You pay a massive tax for that any time you edit your software - since inevitably you're going to end up unpicking hundreds of lines of code that could have been two if statements.

I’ve never seen this abstraction vomit disease be quite this bad in software written in other languages. You can find a bit of it in C#, C++, go and Python. But not as bad as Java. In typescript and rust, most of the code I work with focuses a lot more on directly solving the actual problem at hand.

I don’t think the problem is the language itself. Java is a fine language. But for some reason, it’s become a magnet for a certain kind of developer that I frankly never want to work with. Developers who would never use 5 lines of code when 100 would do. Developers who abstract first and understand the problem they’re solving later. It’s disgusting.

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