3 ms·

The trouble is that tuples are not restricted to local context. JS has made a few steps in allowing us to have objects as compact as a tuple, i.e. {foo, bar, b

by slver 6y ago

The trouble is that tuples are not restricted to local context. JS has made a few steps in allowing us to have objects as compact as a tuple, i.e. {foo, bar, baz}. I think we need more effort in that direction. But keep fields addressable by name at all times. In fact, ordered arguments in functions have the same problem (they're a tuple). Unfortunately that ship has sailed.

pyrale 6y ago
The issue with that is that making tuples a local-only construct is not trivial. A run-of-the-mill tuple is a data type that fits in the type system quite well, it's not costly to create. But a tuple that can only be used locally requires to make a special case in the compiler, and to check it everywhere. Besides, you may end up with divergences in your community about how local a tuple should be allowed to be. Can it be passed to a lambda? Can you map over it in a local context? etc. Overall, deciding where tuples should be used is an easy choice for the developer, and a very hard choice for the language creator.
- slver 6y ago
  If developers used tuples wisely we wouldn't be having this conversation. That's the primary reason why Java has no tuples.
  - pkilgore 6y ago
    Is there any good writing on overuse of tuples? Up until this thread, I just always thought that was a pet peeve of mine. Internally I've tried to make the case that nobody understands the reason a tuple exists except the person who wrote it, and a discriminating union, record, or variant is always a better choice if you're optimizing for the common case (that is, readability).
    - slver 6y ago
      The industry is balkanized on it. Functional languages which tend to model closed systems, with strict types, and hence easier ad-hoc refactoring swear by tuples. OOP platforms which deal with the "outside world" a lot and so need stable API that can evolve without BC breaks avoid tuples. Notice also web APIs virtually never use tuples (everything is objects with named fields both in complex input and virtually all output). A language that targets the browser is going to be inherently open. It has to deal with browser DOM, it has to deal with service APIs, it also has to potentially interact with JS libraries. It'll be an uphill struggle to apply Ocaml style in it.
      - pyrale 6y ago
        > Functional languages which tend to model closed systems [...] OOP platforms which deal with the "outside world" a lot The open vs closed systems logic simply doesn't have any kind of relation with whether one "deals with the outside world", it's about knowing what you're about to receive. And Java, which you quoted earlier, is very much geared for closed systems. On the other hand, Prolog, a language that hardly qualifies as OOP is built to work on open systems. Closed systems language deal with the outside world pretty gracefully, by parsing their inputs. > A language that targets the browser is going to be inherently open. There's been a flurry of closed-system languages for the web in the last decade (e.g. Elm, Fable, etc.), and they work just fine.
        slver 6y ago
        You fail to account for change, and time. As functional languages often do. /s Tuples have coupling order. That's a fact. So if you have tuple [a, b, c, d], then you can maybe extend this by adding ...e, f] at the end, if your parser can ignore extraneous items. But even if your parser can do that, you still can't remove b without BC breaks, because then the rest get shifted, and you have a mess. This is not a problem when the tuple exists only in the confines of some singular unit of code, that gets refactored together. But if it escapes, you have a problem. Because over time, you'll want to change this tuple, and you can't refactor the entire world at once (which is more often than not the issue of functional programming and why it can't scale well).
  - skybrian 6y ago
    Yes, Java has a proliferation of Pair classes instead, along with people arguing against them.
- dgreensp 6y ago
  Making the names part of the type solves this, like structural object types in TypeScript. I’ve come to the conclusion myself that, with the right language syntax supporting it, positional arguments and tuples should be limited to two, maybe three entries, and in the vast majority of cases should be replaced with named/keyword arguments and records even when they are that small (with unnamed, ordered entries being used in cases where there aren’t better names than “first” and “second” or “a” and “b”).

by slver 6y ago

pyrale 6y ago

The issue with that is that making tuples a local-only construct is not trivial. A run-of-the-mill tuple is a data type that fits in the type system quite well, it's not costly to create. But a tuple that can only be used locally requires to make a special case in the compiler, and to check it everywhere. Besides, you may end up with divergences in your community about how local a tuple should be allowed to be. Can it be passed to a lambda? Can you map over it in a local context? etc. Overall, deciding where tuples should be used is an easy choice for the developer, and a very hard choice for the language creator.

slver 6y ago
If developers used tuples wisely we wouldn't be having this conversation. That's the primary reason why Java has no tuples.
- pkilgore 6y ago
  Is there any good writing on overuse of tuples? Up until this thread, I just always thought that was a pet peeve of mine. Internally I've tried to make the case that nobody understands the reason a tuple exists except the person who wrote it, and a discriminating union, record, or variant is always a better choice if you're optimizing for the common case (that is, readability).
  - slver 6y ago
    The industry is balkanized on it. Functional languages which tend to model closed systems, with strict types, and hence easier ad-hoc refactoring swear by tuples. OOP platforms which deal with the "outside world" a lot and so need stable API that can evolve without BC breaks avoid tuples. Notice also web APIs virtually never use tuples (everything is objects with named fields both in complex input and virtually all output). A language that targets the browser is going to be inherently open. It has to deal with browser DOM, it has to deal with service APIs, it also has to potentially interact with JS libraries. It'll be an uphill struggle to apply Ocaml style in it.
    - pyrale 6y ago
      > Functional languages which tend to model closed systems [...] OOP platforms which deal with the "outside world" a lot The open vs closed systems logic simply doesn't have any kind of relation with whether one "deals with the outside world", it's about knowing what you're about to receive. And Java, which you quoted earlier, is very much geared for closed systems. On the other hand, Prolog, a language that hardly qualifies as OOP is built to work on open systems. Closed systems language deal with the outside world pretty gracefully, by parsing their inputs. > A language that targets the browser is going to be inherently open. There's been a flurry of closed-system languages for the web in the last decade (e.g. Elm, Fable, etc.), and they work just fine.
      - slver 6y ago
        You fail to account for change, and time. As functional languages often do. /s Tuples have coupling order. That's a fact. So if you have tuple [a, b, c, d], then you can maybe extend this by adding ...e, f] at the end, if your parser can ignore extraneous items. But even if your parser can do that, you still can't remove b without BC breaks, because then the rest get shifted, and you have a mess. This is not a problem when the tuple exists only in the confines of some singular unit of code, that gets refactored together. But if it escapes, you have a problem. Because over time, you'll want to change this tuple, and you can't refactor the entire world at once (which is more often than not the issue of functional programming and why it can't scale well).
- skybrian 6y ago
  Yes, Java has a proliferation of Pair classes instead, along with people arguing against them.
dgreensp 6y ago
Making the names part of the type solves this, like structural object types in TypeScript. I’ve come to the conclusion myself that, with the right language syntax supporting it, positional arguments and tuples should be limited to two, maybe three entries, and in the vast majority of cases should be replaced with named/keyword arguments and records even when they are that small (with unnamed, ordered entries being used in cases where there aren’t better names than “first” and “second” or “a” and “b”).