←back to thread

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

(www.collabora.com)
611 points LorenDB | 7 comments | 06 May 25 17:51 UTC | HN request time: 0.228s | source | bottom
Show context
thrwyexecbrain ◴[06 May 25 20:15 UTC] No.43909187[source]▶
The C++ code I write these days is actually pretty similar to Rust: everything is explicit, lots of strong types, very simple and clear lifetimes (arenas, pools), non-owning handles instead of pointers. The only difference in practice is that the build systems are different and that the Rust compiler is more helpful (both in catching bugs and reporting errors). Neither a huge deal if you have a proper build and testing setup and when everybody on your team is pretty experienced.

By the way, using "atoi" in a code snippet in 2025 and complaining that it is "not ideal" is, well, not ideal.

replies(5): >>43909244 #>>43909532 #>>43910069 #>>43910728 #>>43913902 #
1. kanbankaren ◴[06 May 25 21:58 UTC] No.43910069[source]▶
The C++ code I wrote 20 years ago also had strong typing and clear lifetimes.

Modern C++ has reduced a lot of typing through type inference, but otherwise the language is still strongly typed and essentially the same.

replies(3): >>43912612 #>>43913304 #>>43934796 #
2. pjmlp ◴[07 May 25 05:48 UTC] No.43912612[source]▶
Unfortunely thanks to the "code C in C++ crowd", there is this urban myth that goodies like proper encapsulation, stronger types, RAII, were not even available in pre-C++98, aka C++ARM.

Meanwhile it was one of the reasons after Turbo Pascal, my next favourite programming language became C++.

For me mastering C, after 1992, only became mattered because as professional, that is something that occasionally I have to delve into so better know your tools even if the grip itself has sharp corners, otherwise everytime the option was constrained to either C or C++, I always pick C++.

3. simonask ◴[07 May 25 08:14 UTC] No.43913304[source]▶
The strong/weak distinction is a bit fuzzy, but reasonable people can have the opinion that C++ is, in fact, loosely/weakly typed. There are countless ways to bypass the type system, and there are implicit conversions everywhere.

It _is_ statically typed, though, so it falls in a weird category of loosely _and_ statically typed languages.

replies(1): >>43922505 #
4. int_19h ◴[08 May 25 02:20 UTC] No.43922505[source]▶
I think that explicit casts really ought to be discounted, since if you're writing one, you are simply getting what you have asked for. This would be like saying that e.g. Modula-2 is weakly typed because it has bitcast.

That aside, the only remaining footgun in C++ is the implicit numeric conversions. What else did you have in mind?

replies(1): >>43923787 #
5. simonask ◴[08 May 25 06:59 UTC] No.43923787{3}[source]▶
I mean, the default behavior of single-argument constructors in C++ is implicit conversion. You have to opt into explicit conversions using the `explicit` keyword on constructors and assignment operators.

Then you have all the shenanigans around placement-new and vtables.

If it isn't downright weak, it's also not particularly strong.

replies(1): >>43924530 #
6. int_19h ◴[08 May 25 09:27 UTC] No.43924530{4}[source]▶
The issue with constructors is a real one, yeah. Although forcing `explicit` on single-argument constructors is a single linter rule (which is a good idea for this exact reason...).

OTOH placement-new is pretty much impossible to use by accident. If used intentionally, I don't see it as being any different from an explicit cast - again, you get what you signed up for.

Interestingly in some ways C++ is arguably more typesafe than languages like Java or C#, given how it handles dynamic type of object during construction & destruction...

7. mathw ◴[09 May 25 08:19 UTC] No.43934796[source]▶
Foundationally though C++ still allows a lot of implicit casts that can and will shoot you in the foot.

You CAN write nice modern code in C++, but the ability to force yourself and all your colleagues to do so in perpetuity isn't really there yet.

Although it might be in the future, which would be nice.