81–90 of 252 posts
I find that structural typing is the most useful thing and unfortunately few languages support it. I'd like a language where: - If I have a class Foo and interface Bar, I should be easily able to pass a Foo where Bar is required, provided that Foo has all the methods that Bar has (sometimes I don't control Foo and can't add the "implements Bar" in it). - I can declare "class Foo implements Bar", but that only means "…
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> Literally think about it. How else do you merge two structs if not using inheritance? What? Using multiple inheritence? That's one of the worst ideas I've ever seen in all of computer science. You can't just glue two arbitrary classes together and expect their invariants to somehow hold true. Even if they do, what happens when both classes implement a method or field with the same name? Bugs. You get bugs. I've bee…
>What? Using multiple inheritence? You just threw this in out of nowhere. I didn't mention anything about "multiple" inheritance. Just inheritance which by default people usually mean single inheritance. That being said multiple inheritance is equivalent to single inheritance of 3 objects. The only problem is because two objects are on the same level it's hard to know which property overrides which. With a single cha…
why inheritance would make it easier?
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Java and C# are already a huge step up from what came before, since they at least introduce the concept of an interface as a distinct thing from a parent class. The fact that you don't notice that is proof that progress does happen, if only slowly.
Java wasn't the first to do that Objective-C (10? years before) had interfaces. Even C++ has that with multiple inheritance - some parents can just be interfaces. As to whether Smalltalk needs interfaces see https://stackoverflow.com/a/7979852/151019 and https://www.jot.fm/issues/issue_2002_05/article1/
C++ does not (or at least did not at the time) have a concept of interfaces. There was a pattern in some development communities for defining interfaces by writing classes that followed particular rules, but no first-class support for them in the language.
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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…
To me (as a Java programmer) inheritance is very useful to reuse code and avoid copy paste. There many cases in which decorators or template methods are very useful and in general I find it "natural" in the sense that the concepts of abstraction and specialization can be found in plenty of real world examples (animals, plants, vehicles etc etc). As usual there is no silver bullet, so it's just a tool and like any oth…
I know we're on Hacker News, but I would have preferred a more explicit title (programming language, not wealth across generations).
> Inheritance was invented by the Simula language
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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…
Of course, in the functional programming community we know that it is pointfree abstraction that makes your software better.
https://wiki.haskell.org/Pointfree
(Please pardon the pun.)
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> 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…
As they say about OOP, everything is somewhere else. The only part of inheritance I’ve ever found useful is allowing objects to conform to a certain interface so that they can fulfill a role needed by a generic function. I’ve always preferred the protocol approach or Rust’s traits for that over classicist inheritance though.
There is this wonderful presentation by Herb Sutter talking about how the C++ concept “class” covers over 20 other abstractions, and that Bjarne’s choice for C++ was the right choice since it offers so much power and flexibility and expressive power in a concise abstraction. Other languages (just like the article) only saw the downsides to such a generic abstraction that they added N times more abstractions (so split…
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…
> a tree probably doesn't represent the fundamental truth of things It does. Trees appear in nature all the time. It's the basis of human society, evolution and many things. Most of programming moves towards practicality rather then fundamental truth. That's why you get languages like golang which are ugly but practical.
Even if you want to claim that trees are a common data structure, that doesn't mean they're appropriate in any specific case. Should we therefore arrange all websites in a tree? Should relational databases be converted to trees, because "they're the basis of human society"? What tosh.
Programming moves toward practicality because software is created to do work. Taxonomies are entirely and completely worthless. The classic Animal -> Mammal -> Cat example for inheritance is a fascinating ontology, and an entirely worthless piece of software.