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how does zig express a trait like Send https://doc.rust-lang.org/std/marker/trait.Send.html https://doc.rust-lang.org/std/marker/trait.Send.html which ensures t

how does zig express a trait like Send https://doc.rust-lang.org/std/marker/trait.Send.html https://doc.rust-lang.org/std/marker/trait.Send.html which ensures that values can safely be moved to another thread, for example when spawning a thread? https://doc.rust-lang.org/std/thread/fn.spawn.html https://doc.rust-lang.org/std/thread/fn.spawn.html

throwawaymaths 2y ago
if you want that you will need a proof checker or something.
- pcwalton 2y ago
  Such as the one Rust provides, and that Zig cannot, due to not being memory safe.
  - rc00 2y ago
    It sounds like you haven't seen projects like this yet: https://github.com/ityonemo/clr https://github.com/ityonemo/clr They're popping up all over. For some reason, Zig folk want Rust things and Rust folk want Zig things.
    - pcwalton 2y ago
      I have seen projects like that, and they're a prime example of what I mean when I want to see arguments in favor of Zig that rely on what Zig can do now, and not what it could potentially do in the future. Ten years ago, C++ folks were also promising memory safety with the ISO C++ Core Guidelines; you don't hear much about that anymore, because it turns out it can't be done while keeping the resulting language C++ (for example, seanbax's work for C++, which is far more advanced than this project, is really awesome, but is essentially a different language).
      - rc00 2y ago
        And what about all the promises of things making it out of Rust Nightly? When it comes to Zig, one crowd says it's too early because it's not 1.0 fast enough. And now, are you saying that the feature development is basically done? What point are you trying to make?
        pcwalton 2y ago
        The point I'm making is that I don't believe Zig can be made meaningfully memory safe without breaking compatibility to the extent that memory-safe Zig would effectively be a different language, any more than C can.
        pron 2y ago
        I tend to agree, but writing code in a memory-safe language is not the goal. The relevant goal on that particular front (and it is not the only goal people have when writing programs) is to maximise the resulting program's correctness within some effort budget and other requirements (such as memory consumption etc.). Using a memory-safe language is one approach toward achieving that goal, but if that safety comes at a cost of added effort, then showing that's the best approach depends on claims that are hard to verify without a lot more empirical data. The only theoretical justification could be that more soundness results in more practical correctness, but if that were the case then there are languages that offer more soundness than Rust. In other words, if Rust is generally superior to Zig because it offers more soundness, then other languages are superior still. Indeed, soundness is not considered the best approach to attaining every property in general because it can be more expensive than other approaches that achieve the desired outcome, and Rust clearly recognises that. Rather, both languages' correctness-related claims rely on them being in some better or worse effort/correctness sweet spot, and that can only be measured empirically for those two specific languages. Crucially, results comparing Rust to C or C++ are not relevant. Zig offers more soundness than C, and even if it offers the same soundness as C++ (and I disagree -- I think it offers more) the language's claim is that its simplicity assists correctness. We can only tell to what extent that is true with more empirical observation; I don't think there can be any good guess made here regarding the size of the effect.

throwawaymaths 2y ago

if you want that you will need a proof checker or something.

pcwalton 2y ago
Such as the one Rust provides, and that Zig cannot, due to not being memory safe.
- rc00 2y ago
  It sounds like you haven't seen projects like this yet: https://github.com/ityonemo/clr https://github.com/ityonemo/clr They're popping up all over. For some reason, Zig folk want Rust things and Rust folk want Zig things.
  - pcwalton 2y ago
    I have seen projects like that, and they're a prime example of what I mean when I want to see arguments in favor of Zig that rely on what Zig can do now, and not what it could potentially do in the future. Ten years ago, C++ folks were also promising memory safety with the ISO C++ Core Guidelines; you don't hear much about that anymore, because it turns out it can't be done while keeping the resulting language C++ (for example, seanbax's work for C++, which is far more advanced than this project, is really awesome, but is essentially a different language).
    - rc00 2y ago
      And what about all the promises of things making it out of Rust Nightly? When it comes to Zig, one crowd says it's too early because it's not 1.0 fast enough. And now, are you saying that the feature development is basically done? What point are you trying to make?
      - pcwalton 2y ago
        The point I'm making is that I don't believe Zig can be made meaningfully memory safe without breaking compatibility to the extent that memory-safe Zig would effectively be a different language, any more than C can.
        pron 2y ago
        I tend to agree, but writing code in a memory-safe language is not the goal. The relevant goal on that particular front (and it is not the only goal people have when writing programs) is to maximise the resulting program's correctness within some effort budget and other requirements (such as memory consumption etc.). Using a memory-safe language is one approach toward achieving that goal, but if that safety comes at a cost of added effort, then showing that's the best approach depends on claims that are hard to verify without a lot more empirical data. The only theoretical justification could be that more soundness results in more practical correctness, but if that were the case then there are languages that offer more soundness than Rust. In other words, if Rust is generally superior to Zig because it offers more soundness, then other languages are superior still. Indeed, soundness is not considered the best approach to attaining every property in general because it can be more expensive than other approaches that achieve the desired outcome, and Rust clearly recognises that. Rather, both languages' correctness-related claims rely on them being in some better or worse effort/correctness sweet spot, and that can only be measured empirically for those two specific languages. Crucially, results comparing Rust to C or C++ are not relevant. Zig offers more soundness than C, and even if it offers the same soundness as C++ (and I disagree -- I think it offers more) the language's claim is that its simplicity assists correctness. We can only tell to what extent that is true with more empirical observation; I don't think there can be any good guess made here regarding the size of the effect.