Hacker News new | ask | show | jobs
by weberc2 2613 days ago
You misunderstood my post. I said I haven’t seen a useful getter abstraction. Not all data access is via a method nor is it always abstract.

I specifically object to the useless abstraction, not the boilerplate (boilerplate is cheap).

1 comments

I think we're coming at it from different angles. My point is that there shouldn't be any abstraction to write, and it should just be the way the language works. Primitive slot access in Java is not just a get/set interface, it's a get/set interface that also specifies implementation characteristics and what the code will be capable of in the future. It should be in the language so that you can have primitive slots, but it shouldn't be part of the interface you expose for your own modules, because adding pointless coupling to your code does nothing but restrict future changes. Languages should not provide an easy shortcut for writing interfaces like that.

I don't view it as a useless abstraction, because I view it as the natural way of things. I view specifying that your get/set implementation is and always will be implemented as slot access to be uselessly sharing implementation details that does nothing but freeze your current implementation strategy.

I think a better question is when that abstraction gets in your way. When does it bother you that nullary functions aren't reading memory locations? Why do you feel that's an essential thing to specify in your public interface, as a default? There's nothing stopping you from writing code in Python and mentally modelling o.x as slot access, because it follows the interface you want from it.

If you only care because it's something extra you have to do, then that's what I meant by boilerplate. I think it's a misfeature of Java's that it presents a model where that's something extra you have to do.

> My point is that there shouldn't be any abstraction to write, and it should just be the way the language works.

I understand your point, but I think you misunderstand what "abstraction" means. "abstraction" doesn't mean "function" (although functions are frequently used to build abstractions), and if you have "dynamic properties" (or whatever you'd like to call them) a la Python, then you're still abstracting. My point is that abstracting over property access (regardless of property-vs-function syntax) is not useful, or rather, I'm skeptical that it's useful.

> I think a better question is when that abstraction gets in your way. When does it bother you that nullary functions aren't reading memory locations? Why do you feel that's an essential thing to specify in your public interface, as a default? There's nothing stopping you from writing code in Python and mentally modelling o.x as slot access, because it follows the interface you want from it.

I think this is a good question, because it illustrates a philosophical difference--if I understand your position correctly, you'd prefer to be as abstract as possible until it's problematic; I prefer to be as concrete as possible until abstraction is necessary. There's a lot of mathematical elegance in your position, and when I'm programming for fun I sometimes try to be maximally abstract; however, when I'm building something and _working with people_, experience and conventional wisdom tells me that I should be as concrete and flat-footed as possible (needless abstraction only makes it harder to understand).

To answer your question, that abstraction gets in your way all the time. The performance difference between a memory access (especially a cache-hit) and an HTTP request is several orders of magnitude. If you're doing that property access in a tight loop, you're wasting time on human-perceivable timescales. While you can "just be aware that any given property access could incur a network call", that really sucks for developers, and I see them miss this all the time (I work in a Python shop). We moved away from this kind of "smart object" pattern in our latest product, and I think everyone would agree that our code is much cleaner as a result (obviously this is subjective).

TL;DR: It's useful to have semantics for "this is a memory access", but that's unrelated to my original point :)