Comment by andrepd | Hacker News Reader

Comment by andrepd | Hacker News Reader

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I disagree with almost everything you said in that post; what's more, you're objectively wrong. Let's look at your claims.

>Every new C++ article about the latest "improvements" to the language tends to confirm my belief that C++ developers are masochists. They don't seem to be interested in actually improving the language and making in better and easier at creating useful software. [...] The entire ecosystem feels like a infinite pile of new features fixing old ones, bringing new flaws in the process.

Can you give a concrete example? C++ evolution can be divided in roughly two eras: C++98, and Modern C++ (C++11 and above). This latter introduces a new philosophy, an expansion of features that make it look like a completely new language indeed. From ubiquitous type deduction, to lambdas, to compile-time computation without TMP, the language has introduced powerful new abstractions, always with the trademark "zero cost" that gives C++ its power.

>[Code snippet]

>I don't want a language with magic.

What about that snippet is magic that leaves you so appalled? You got a great (new) feature: guaranteed compile-time conditionals with the same syntax as regular if statements. Depending on whether the object has serialize or not, the code will instantiate to each of the branches, guaranteeing elision of a potentially expensive runtime check and branch.

>Show me simplicity and elegance. [...] Show me how I don't have to choose between value, reference, raw pointer, unique_ptr, shared_ptr, etc, to pass a damn parameter to your function.

Show me a language that simpler and more elegant than C++, where you don't have to worry about choosing how to pass parameters, or manage memory, and that still is as fast as C++. You simply can't, because there's no such thing. C++ delivers ZERO-COST ABSTRACTIONS, that's its power, that's its raison d'être. No other language I'm aware of that delivers this, apart from maybe Rust or D.

--

I realize it's hip to hate on C++, but please keep it rational.

> Show me a language that simpler and more elegant than C++, where you don't have to worry about choosing how to pass parameters, or manage memory, and that still is as fast as C++.

As someone who built their career on memory constrained, fast code in C++ I'm gonna have to say that Rust is simpler and more elegant.

You've got your zero cost abstractions, heck I can decided static vs dynamic dispatch at compile time. Lots of things are more explicit leading to less foot-guns that you see with implicit type conversion and the like. Borrow-checker catches all those nasty dataraces and ownership problems up front. I've yet to run across anything I could do in C++ that I can't do in Rust.

Listen, I love C++ but I think you may want to expand your horizons a bit before declaring it the best language ever in this space.

Even if Rust is better than C++, that doesn’t mean C++ is bad.

Yes, actually, it does. Because C++'s mantra has always been zero cost abstractions. And people have defended the language because "you can't do better and still have the same performance". Well, it seems you can.

Languages are never compared across a single dimension (except to prove a point on the internet).

Rust does come with a different bag of complexity. I'm thrilled to see competition with C++ in this space finally and super excited about Rust, but let's not pretend Rust is easy, either. It has a notoriously monsterous learning curve (which is why there's a major focus to fix that curve: https://github.com/rust-lang/rust-roadmap/issues/17 )

And in this particular context Rust also still forces you to figure out how to pass parameters and manage memory. It "just" helps you with when to call free, which std::unique_ptr also helps you with. Rust makes it a compile error to have a bug, which is awesome, but the "you have to figure out memory allocation & layout" complexity is still mostly there.

> It has a notoriously monsterous learning curve

That learning curve exists in C++ too, it's just hidden under the iceberg of 'interesting' runtime behavior. There's nothing like trying to printf a data race only to have the print call insert a fence and make your data race disappear.

> And in this particular context Rust also still forces you to figure out how to pass parameters and manage memory.

This is a lot simpler in Rust. Everything is value type by default, Box<T> for heap allocations, which even then are managed mostly for you via RAII(yeah I know there's std::unique_ptr but you still also have new, delete, new[], delete[], etc). Parameter types are value, mut ref or const ref. Move semantics are implicit if you have a value type. You don't have const/volatile/etc function qualifiers.

implicit type conversion(esp constructors) can be a total bastard and trip you up in nasty ways. Even more annoying if you're trying to bit-pack or do clever math.

Rust got to learn from a lot of C++'s mistakes and is to me a better language for it.

> This is a lot simpler in Rust. Everything is value type by default, Box<T> for heap allocations, which even then are managed mostly for you via RAII(yeah I know there's std::unique_ptr but you still also have new, delete, new[], delete[], etc). Parameter types are value, mut ref or const ref. Move semantics are implicit if you have a value type. You don't have const/volatile/etc function qualifiers.

That's not simpler at all - it's basically the same. C++ is also value type by default and you have to ask for heap allocations. And just like in C++ you have types in Rust that look like stack allocations but aren't, like Vec.

So no, it's just value type otherwise Box<T>. That's not true in the slightest. And you need to specify in your function if it's taking ownership or not in addition to whether or not it's pass-by-value or pass-by-reference.

Other than new/delete it's the same shit, just a different syntax.

Rust got to break backwards compatibility which allowed it to remove a lot of C/C++'s old mistakes, yes, but the raw complexity is still entirely there, and very nearly identical.

> That's not simpler at all - it's basically the same

Oh, you mean like how you have rvalues, lvalues, xvalues, glvalues and prvalues[1]. In Rust you have value, ref and mut ref.

You also don't specify ownership of passed pointers. So you need to encode that into your function documentation, as opposed to Rust where only value types can change ownership.

> And just like in C++ you have types in Rust that look like stack allocations but aren't, like Vec.

Never said anything about that, we're just talking about parameter types here, of course you can have value types take ownership of stack allocations(Box<T>, std::unique_ptr and their variants).

> And you need to specify in your function if it's taking ownership or not in addition to whether or not it's pass-by-value or pass-by-reference.

Not in the case of Rust, value types are the only thing that can take ownership(even Arc/Rc return value types when you clone()). Refs just allow temporary access in a mutable/const way for the lifecycle of the function.

> Rust got to break backwards compatibility which allowed it to remove a lot of C/C++'s old mistakes

Thanks for proving my point. I've never seen a C++ codebase that didn't use some of C++'s mistakes.

[1] https://stackoverflow.com/questions/3601602/what-are-rvalues...

> Oh, you mean like how you have rvalues, lvalues, xvalues, glvalues and prvalues[1]. In Rust you have value, ref and mut ref.

That is not a reasonable comparison and you know it. rvalues & lvalues are the only things in C++ that you ever care about in the slightest unless you're writing a compiler, and if you're writing a compiler then Rust has things like xvalues, too (how do you think the Drop trait works?)

Answer me a simple question, why does std::move exist then?

(here's a hint, Rust doesn't need xvlaues because every value already has an associated lifetime)

I believe the only thing that can be said with certainty about Rust when compared to C++ is that it's safer.

Simplicity in the sense of easy to understand is an adjective I would apply to languages such as golang, Swift or even Java. C++ and Rust are complicated languages, because they allow low-level control of the implementation and they insist on the programmer thinking deeply about resource management.

Elegance is likewise a property I would not associate with Rust: resource management is clumsy and leaks into the syntax everywhere, it ends up defining how the language looks like.

This is the paradox: Every new language feature in C++ has, as you say, a rational argument for inclusion. Yet when you combine them, you get a language that I will never use if I have a choice.

> No other language I'm aware of that delivers this, apart from maybe Rust or D.

Reminds me of a great campaign speech from Donald Trump where he praises the border wall, saying there will be no way anyone could get down once they managed to climb it. Except maybe a rope. Good job proving your point by shooting yourself in the foot.

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