Matt Godbolt sold me on Rust by showing me C++ • Hacker News Board

Re: Matt Godbolt sold me on Rust by showing me C++

#261

Post by kragen » Wed, May 07, 2025, 3:55 AM UTC

bigstrat2003 wrote: post #235

noelnh wrote: post #199

Earlier quoted context omitted.

Could you elaborate on those points, I'm genuinely curious? So far, I have found the Rust community to be immensely helpful, much more so than I experienced the C++ community. Granted, that's quite some time ago and might be at least partially caused by me asking fewer downright idiotic questions. But still, I'm interested in hearing about your experiences.

The Rust community is helpful... but also quite political and extremely hostile to anyone who doesn't share those politics. Even something as anodyne as saying "let's keep politics out of technical discussion" is frequently met with hostility (because many community members believe that tech is inherently political and that trying to keep politics out is really just a bad faith attempt to frame things in terms of the…

JeanHeyd's side of the RustConf thing: https://thephd.dev/i-am-no-longer-speaking-at-rustconf-2023

Re: Matt Godbolt sold me on Rust by showing me C++

#262

Post by dcdgo » Wed, May 07, 2025, 3:56 AM UTC

GardenLetter27 wrote: post #14

It's a shame Rust doesn't have keyword arguments or named tuples to make handling some of these things easier without Args/Options structs boilerplate.

Rust Tuples can be destructured into named variables, or Enums can be used as Monads which give a label to a tuple of variables. Rust Enums are real fun to use so I encourage you to dive in. https://doc.rust-lang.org/rust-by-example/custom_types/enum....

Re: Matt Godbolt sold me on Rust by showing me C++

#263

Post by throwaway2037 » Wed, May 07, 2025, 3:57 AM UTC

loeg wrote: post #204

jchw wrote: post #89

Earlier quoted context omitted.

Google has been doing a very similar, but definitely somewhat uglier, thing with StatusOr and Status (as seen in absl and protobuf) for quite some time. A long time ago, there was talk about a similar concept for C++ based on exception objects in a more "standard" way that could feasibly be added to the standard library, the expected class. And... in C++23, std::expected does exist[1], and you don't need to use excep…

Facebook's Folly has a similar type: folly::Expected (dating to 2016).

If I had to guess, that idea came from Andrei Alexandrescu.

Re: Matt Godbolt sold me on Rust by showing me C++

#264

Post by dwattttt » Wed, May 07, 2025, 3:59 AM UTC

ackfoobar wrote: post #46

dvt wrote: post #15

Earlier quoted context omitted.

Maybe contrarian, but imo the `Result` type, while kind of nice, still suffers from plenty of annoyances, including sometimes not working with the (manpages-approved) `dyn Error`, sometimes having to `into()` weird library errors that don't propagate properly, or worse: `map_err()` them; I mean, at this point, the `anyhow` crate is basically mandatory from an ergonomics standpoint in every Rust project I start. Also,…

> the `anyhow` crate is basically mandatory from an ergonomics standpoint in every Rust project I start If you use `anyhow`, then all you know is that the function may `Err`, but you do not know how - this is no better than calling a function that may `throw` any kind of `Throwable`. Not saying it's bad, it is just not that much different from the error handling in Kotlin or C#.

I find myself working through a hierarchy of error handling maturity as a project matures.

Initial proof of concepts just get panics (usually with a message).

Then functions start to be fallible, by adding anyhow & considering all errors to still be fatal, but at least nicely report backtraces (or other things! context doesn't have to just be a message)

Then if a project is around long enough, swap anyhow to thiserror to express what failure modes a function has.

Re: Matt Godbolt sold me on Rust by showing me C++

#265

Post by almostgotcaught » Wed, May 07, 2025, 3:59 AM UTC

cratermoon wrote: post #255

almostgotcaught wrote: post #250

Earlier quoted context omitted.

> Every single package manager couldn’t handle my very basic and very popular dependencies Well there's your problem - no serious project uses one. > I’m convinced it’s a bunch of masochists People use cpp because it's a mature language with mature tooling and an enormous number of mature libraries. Same exact reason anyone uses any language for serious work.

How can you simultaneously call cpp a mature language with mature tooling and acknowledge that there's no working package manager used by any "serious" project?

Do you people really not realize how completely asinine you sound with these lowbrow comments? I'll give you a hint: did you know that C also has no package manager?

Re: Matt Godbolt sold me on Rust by showing me C++

#266

Post by brooke2k » Wed, May 07, 2025, 4:03 AM UTC

kllrnohj wrote: post #248

codedokode wrote: post #103

Earlier quoted context omitted.

It's pretty difficult to have no panics, because many functions allocate memory and what are they supposed to do when there is no memory left? Also many functions use addition and what is one supposed to do in case of overflow?

> Also many functions use addition and what is one supposed to do in case of overflow? Honestly this is where you'd throw an exception. It's a shame Rust refuses to have them, they are absolutely perfect for things like this...

I'm confused by this, because a panic is essentially an exception. They can be thrown and caught (although it's extremely discouraged to do so).

The only place where it would be different is if you explicitly set panics to abort instead of unwind, but that's not default behavior.

Re: Matt Godbolt sold me on Rust by showing me C++

#267

Post by const_cast » Wed, May 07, 2025, 4:07 AM UTC

cratermoon wrote: post #255

almostgotcaught wrote: post #250

Earlier quoted context omitted.

> Every single package manager couldn’t handle my very basic and very popular dependencies Well there's your problem - no serious project uses one. > I’m convinced it’s a bunch of masochists People use cpp because it's a mature language with mature tooling and an enormous number of mature libraries. Same exact reason anyone uses any language for serious work.

How can you simultaneously call cpp a mature language with mature tooling and acknowledge that there's no working package manager used by any "serious" project?

Package managers per language are a (relatively) new endeavor. The oldest language I can think of that widely adopted it was Perl. Although, perl was quite ahead of it's time in a lot of ways, and php undid some the work of perl and went back to popularizing include type dependencies instead of formal modules with a package manager.

C++ "gets away" with it because of templates. Many (most?) libraries are mostly templates, or at the very least contain templates. So you're forced into include-style dependencies and it's pretty painless. For a good library, it's often downloading a single file and just #include-ing it.

C++ is getting modules now, and maybe that will spur a new interest in package managers. Or maybe not, it might be too late.

Re: Matt Godbolt sold me on Rust by showing me C++

#268

Post by const_cast » Wed, May 07, 2025, 4:10 AM UTC

Ygg2 wrote: post #150

jsat wrote: post #64

Earlier quoted context omitted.

Had the same thought... It's backwards that any language isn't using named parameters at this point.

Named parameters do come with a large footgun. Renaming your parameters is a breaking change. Especially if you're coming from different langs.

This only really applies to languages that don't check this at compile-time. I don't consider compile-time errors a foot gun. I mean, it should be impossible for that kind of bad code to ever get merged in most reasonable CI/CD processes.

Re: Matt Godbolt sold me on Rust by showing me C++

#269

Post by nailer » Wed, May 07, 2025, 4:11 AM UTC

> Before we go any further, let me just say he acknowledges floating point is not right for price and later talks about how he usually deals with it. But it makes for a nice example, bear with us.

OK but "this makes for a nice example" is silly, given that the only reason the example throws an error is that you used a float here, when both `quantity` and `price` would have been ints.

    error[E0308]: arguments to this function are incorrect
    --> order/order-1.rs:7:5
      |
    7 |     send_order("GOOG", false, 1000.00, 100); // Wrong
      |     ^^^^^^^^^^                -------  --- expected `f64`, found `{integer}`
      |                               |
      |                               expected `i64`, found `{float}`

I love Rust, but this is artificial.

Re: Matt Godbolt sold me on Rust by showing me C++

#270

Post by adgjlsfhk1 » Wed, May 07, 2025, 4:13 AM UTC

almostgotcaught wrote: post #265

cratermoon wrote: post #255

Earlier quoted context omitted.

How can you simultaneously call cpp a mature language with mature tooling and acknowledge that there's no working package manager used by any "serious" project?

Do you people really not realize how completely asinine you sound with these lowbrow comments? I'll give you a hint: did you know that C also has no package manager?

Yeah, and it's also much worse for it. There's a reason everyone in C uses their own linked list implementation and it's not because it's a platonic ideal of perfect software.