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These Java features are ruined by not allowing mutable variables to be captured. Having to do the 1-element array trick when the compiler could just do it for m

These Java features are ruined by not allowing mutable variables to be captured. Having to do the 1-element array trick when the compiler could just do it for me is insane. If you are making JavaScript look good you are failing as a language.

cess11 2y ago
Typically I can use a forEach in such cases, and when I can't it's probably an incrementer and the IDE just switches out my int as an automatic solution to its complaint. I think its OK to be reminded that the context is mainly immutable when chaining on a stream. Method polymorphism to achieve default parameter values is a much worse nuisance, but not particularly hard to get used to when one decides to focus on the problem rather than the inevitable warts of a broadly useful programming language. Edit: Also a pretty weird complaint in a thread about a programming language where pretty much all the basic data structures are immutable. Maybe take it to the top and make the quip about worse than JavaScript with regards to Clojure?
- ErikCorry 2y ago
  Doesn't the forEach method on arrayList have the exact same issue?
kaba0 2y ago
You mean not having the error that go just fixed by changing the language is a problem?
- ErikCorry 2y ago
  JS has this error too, but nothing forces Java to have this issue if they fix the no-mutable-captures problem. Dart got this right from the start. Here's JS showing the same issue. for (var i = 0; i < 10; i++) { array.push(() => i) } array.forEach((fn) => console.log(fn())) // Prints 10 every time. The correct fix is that each loop iteration gets a fresh i instead of i just being mutated. Currently you can't see the difference in Java between there-is-only-one-i and there-is-a-fresh-i-every-time, so Java is free to do this right.
  - cess11 2y ago
    Here's what I'd do: array = []; function clos(val) { return () => val; } for (var i = 0; i < 10; i++) { array.push(clos(i)); } array.forEach(fn => console.log(fn())); This outputs 0-9 instead of 10, though I'm just a silly self-taught person that never got schooled at these things, maybe there is some reason not to use closures that I don't know about.
    - ifwinterco 2y ago
      These days in JS you can just use let instead of var and it will work, but in itself that inconsistency is a bit weird
      - cess11 2y ago
        Yeah, let/const is what I tend to use. Here I wanted to change someone else's code as little as possible. Edit: Oh, right, it also solves the 10-issue. Thanks, didn't realise at first.

cess11 2y ago

Typically I can use a forEach in such cases, and when I can't it's probably an incrementer and the IDE just switches out my int as an automatic solution to its complaint. I think its OK to be reminded that the context is mainly immutable when chaining on a stream. Method polymorphism to achieve default parameter values is a much worse nuisance, but not particularly hard to get used to when one decides to focus on the problem rather than the inevitable warts of a broadly useful programming language. Edit: Also a pretty weird complaint in a thread about a programming language where pretty much all the basic data structures are immutable. Maybe take it to the top and make the quip about worse than JavaScript with regards to Clojure?

ErikCorry 2y ago
Doesn't the forEach method on arrayList have the exact same issue?

kaba0 2y ago

You mean not having the error that go just fixed by changing the language is a problem?

ErikCorry 2y ago
JS has this error too, but nothing forces Java to have this issue if they fix the no-mutable-captures problem. Dart got this right from the start. Here's JS showing the same issue. for (var i = 0; i < 10; i++) { array.push(() => i) } array.forEach((fn) => console.log(fn())) // Prints 10 every time. The correct fix is that each loop iteration gets a fresh i instead of i just being mutated. Currently you can't see the difference in Java between there-is-only-one-i and there-is-a-fresh-i-every-time, so Java is free to do this right.
- cess11 2y ago
  Here's what I'd do: array = []; function clos(val) { return () => val; } for (var i = 0; i < 10; i++) { array.push(clos(i)); } array.forEach(fn => console.log(fn())); This outputs 0-9 instead of 10, though I'm just a silly self-taught person that never got schooled at these things, maybe there is some reason not to use closures that I don't know about.
  - ifwinterco 2y ago
    These days in JS you can just use let instead of var and it will work, but in itself that inconsistency is a bit weird
    - cess11 2y ago
      Yeah, let/const is what I tend to use. Here I wanted to change someone else's code as little as possible. Edit: Oh, right, it also solves the 10-issue. Thanks, didn't realise at first.