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I want to be interested in Rust, but then I see a line of code like this in the post: let decrement = move |_| set_value.update(|value| *value -= 1); Maybe I'

I want to be interested in Rust, but then I see a line of code like this in the post: let decrement = move |_| set_value.update(|value| *value -= 1); Maybe I've lost that interest I once had in learning language syntax.. I just don't really understand this intuitively and the barrier to understanding this line feels unnecessary. When I compare Rust with JS/TS, Python, or even Swift I feel like those other languages are created in a way that's easy to pick up and transfer knowledge from other languages, then the deeper parts of the language are easily accessible once you're introduced to the basics.

duped 4y ago
I mean compare to using arrow functions and it's almost identical let decrement = () => set_value.update((value) => value -1); The difference is that Rust isn't garbage collected and has reference value semantics, which is where the *value -= 1 comes in.
- willio58 4y ago
  It's funny, I almost noted that arrow functions are a definite oddity of JS that I could see people thrown off by.
  - marcosdumay 4y ago
    > oddity of JS I can't think on any modern language that lacks some short syntax for lambdas. Hell, it's very easy to make a point that lacking short syntax for lambdas make a language not modern and unusable for our current standards.
    - willio58 4y ago
      I'm a little confused what you mean by JS lacking a short syntax for lambdas. let multiply = (a, b) => a * b; Is this not a lambda?
      - kaba0 4y ago
        Parent means that basically every language has lambdas, so it could hardly be an odd thing.
        willio58 4y ago
        Ohh! Thanks for clarifying
      - earthling8118 4y ago
        You've missed their point entirely. It was never stated that JS was lacking this, rather than most languages DON'T lack it.
- ansc 4y ago
  I like how you skipped the hardest part that requires most Rust knowledge; the `move`
  - duped 4y ago
    Ok fine, "Rust doesn't have a garbage collector and has reference value semantics and ownership semantics." My point is that the syntax isn't a problem, it's that Rust has very different semantics from the GC'd languages in the original comment and it all has to do with memory management.
supportlocal4h 4y ago
Compare your Rust with my JS: let decrement = _=>set_value.update(value => value -= 1) I don't understand your complaint about syntax. The real difference here is the concept of a move and a dereference. JS lacks these concepts and naturally has no syntax for them.

duped 4y ago

I mean compare to using arrow functions and it's almost identical let decrement = () => set_value.update((value) => value -1); The difference is that Rust isn't garbage collected and has reference value semantics, which is where the *value -= 1 comes in.

willio58 4y ago
It's funny, I almost noted that arrow functions are a definite oddity of JS that I could see people thrown off by.
- marcosdumay 4y ago
  > oddity of JS I can't think on any modern language that lacks some short syntax for lambdas. Hell, it's very easy to make a point that lacking short syntax for lambdas make a language not modern and unusable for our current standards.
  - willio58 4y ago
    I'm a little confused what you mean by JS lacking a short syntax for lambdas. let multiply = (a, b) => a * b; Is this not a lambda?
    - kaba0 4y ago
      Parent means that basically every language has lambdas, so it could hardly be an odd thing.
      - willio58 4y ago
        Ohh! Thanks for clarifying
    - earthling8118 4y ago
      You've missed their point entirely. It was never stated that JS was lacking this, rather than most languages DON'T lack it.
ansc 4y ago
I like how you skipped the hardest part that requires most Rust knowledge; the `move`
- duped 4y ago
  Ok fine, "Rust doesn't have a garbage collector and has reference value semantics and ownership semantics." My point is that the syntax isn't a problem, it's that Rust has very different semantics from the GC'd languages in the original comment and it all has to do with memory management.

supportlocal4h 4y ago

Compare your Rust with my JS: let decrement = _=>set_value.update(value => value -= 1) I don't understand your complaint about syntax. The real difference here is the concept of a move and a dereference. JS lacks these concepts and naturally has no syntax for them.