How to not rewrite it in Rust

Post by Gaelan » Wed, Oct 23, 2019, 2:41 PM UTC

zeroxfe wrote: post #22

mmaurizi wrote: post #19

Earlier quoted context omitted.

Passing around pointers to objects on the stack. In another language you'd risk having a pointer to invalid memory when the function returns if the pointer escapes the function, and so it is advised to use pointers to objects on the stack sparingly if at all. In rust, the compiler will statically determine if a pointer to an object on the stack could escape the function, and if so will fail to compile.

> In another language you'd risk having a pointer to invalid memory when the function returns if the pointer escapes the function, and so it is advised to use pointers to objects on the stack sparingly if at all. Just a nitpick, this is only true for non-garbage-collected (or refcounted) languages. :-)

Post by steveklabnik » Wed, Oct 23, 2019, 2:44 PM UTC

StreamBright wrote: post #20

steveklabnik wrote: post #8

Earlier quoted context omitted.

All of Rust's complexity for strings comes out of complexity due to UTF-8. Well, a tiny bit comes from the fact that Rust has pointers too, but most of it is UTF-8. Did you happen to read the book? We cover strings early because this is a common pain point. Also, if you have something more detailed than "get strings out of libraries", I can give better advice. It's tough to tell what the actual issue is.

Like this: use sha2::{Sha256, Digest}; fn main() { let mut hasher = Sha256::new(); hasher.input(b"hello world"); let result = hasher.result(); ?? } How do I get a string with the hash value? Which chapter of which book should I read?

  use sha2::{Sha256, Digest};
  use base64;
  
  fn main() {
      let mut hasher = Sha256::new();
      hasher.input(b"hello world");
      let result = hasher.result();
      let encoded = base64::encode(&result);
    
      assert_eq!("uU0nuZNNPgilLlLX2n2r+sSE7+N6U4DukIj3rOLvzek=", encoded);
  }

Post by steveklabnik » Wed, Oct 23, 2019, 2:45 PM UTC

lmkg wrote: post #29

steveklabnik wrote: post #15

Earlier quoted context omitted.

> so this sounds like it's describing a bad way to rewrite something in Rust, which is not the case. I think this kind of title is trying to do exactly that, or at least, that's how I took it. > It also isn't the wording used in the original article title. This is a good reason to switch it, for sure. I didn't realize this, if you had led with that, I wouldn't have said anything :)

> I think this kind of title is trying to do exactly that, or at least, that's how I took it I took the exact opposite: This article is describing an alternative to RiiR, so that RiiR is avoided when not needed.

Post by steveklabnik » Wed, Oct 23, 2019, 2:46 PM UTC

fjp wrote: post #30

steveklabnik wrote: post #8

Earlier quoted context omitted.

All of Rust's complexity for strings comes out of complexity due to UTF-8. Well, a tiny bit comes from the fact that Rust has pointers too, but most of it is UTF-8. Did you happen to read the book? We cover strings early because this is a common pain point. Also, if you have something more detailed than "get strings out of libraries", I can give better advice. It's tough to tell what the actual issue is.

Which book? I'm just starting the O'Reilly book, coming from Python

Post by atq2119 » Wed, Oct 23, 2019, 2:46 PM UTC

infogulch wrote: post #21

readams wrote: post #16

Earlier quoted context omitted.

That's not true. If you build from a dist tarball, you do not need auto tools installed. You usually do if you build from a git repo, however.

How/why is a dist tarball not exactly the same as a zipped up git tree?