31–40 of 144 posts
Is learning modern C++ worth the effort in 2021? I know classic c++, but don't really use it anymore.
I would say, yes. C++11 is, in some ways, a totally new and more powerful language. I was sold on it as soon as I started learning. C++14 and C++17 add some useful features. I know basically nothing about C++20.
Earlier quoted context omitted.
I would say, yes. C++11 is, in some ways, a totally new and more powerful language. I was sold on it as soon as I started learning. C++14 and C++17 add some useful features. I know basically nothing about C++20.
As a non-C++ professional programmer question, what's the occurrence of the codebases you work on, where the standard is significantly/fundamentally C++ 14/17?
If you have a C++11 code base, you don't really lose anything by adopting C++17, and you do gain a few things.
Part of this is that I’m tired, but it blows my mind how difficult C++ coroutines are as someone who considers themselves decent at C++ (although maybe I’m not) and uses coroutines in other languages. The amount of code needed to do almost nothing is extraordinary, and putting it all together doesn’t seem like you would often get on your first try. I get that new keywords basically can’t be added, but man, that’s pai…
I believe that the design is both unneededly complex and too unflexible, but this is the only design that managed to get enough traction to get into the standard and it took forever. There are competing designs and improvements, we will have to see if they will make it into the standard.
Part of this is that I’m tired, but it blows my mind how difficult C++ coroutines are as someone who considers themselves decent at C++ (although maybe I’m not) and uses coroutines in other languages. The amount of code needed to do almost nothing is extraordinary, and putting it all together doesn’t seem like you would often get on your first try. I get that new keywords basically can’t be added, but man, that’s pai…
C++ coroutines as they are in the standard are not really intended to the everyday programmer (1), but rather for library implementers who will use and abstract them into higher level features. 1: like most of C++ one would way
Basically how the library realizes this is opaque to the user and indeed it does things like reuse low level primitives available in each of the platforms. Basically, at it's lowest level it is simply syntactic sugar for callback based implementations common in platforms that have things like Futures, Promises, etc.
In fact it's easy to integrate any third party library that provides similar constructs and pretend that they are suspend functions. E.g. the suspendCancellableCoRoutine builder can take anything that has a success and fail callback and turn it into suspending code blocks. For example Spring supports coroutines and flows out of the box now and provides deep integration with its own reactive webflux framework. So, you can write a controller that is a suspend function that returns a flow and it just works as a nice reactive endpoint.
I actually would expect that these new C++ capabilities will also find their way into Kotlin's native coroutine implementation eventually. Kotlin native is still in Beta but seems popular for cross platform IOS and Android library development currently.
Kotlin's coroutine library took quite a while to get right for the Kotlin developers and evolved a lot between Kotlin 1.2 and 1.4. Parts of it are still labelled as experimental. Particularly, reactive flows are a relatively late addition and have already had a big impact on e.g. Android and server-side programming.
Is learning modern C++ worth the effort in 2021? I know classic c++, but don't really use it anymore.
* ranges means that we're starting to get composable algorithms. Compared to doing `for_each` and then `accumulate` on a container, you can compose both operations into one reusable "pipeline" of operations. I really grew to like this from other languages, and am glad that C++ is starting to get it * modules will help a lot, but I doubt we'll get widespread use for another year at least (until cmake has it; build2 has it, but that's a bit esoteric even though it's very pleasant to work with) * concepts make working with template-laden code a lot easier. Most of the tricks for obscure SFINAE removal of templates are no longer necessary; one can just express it in a "positive" way as if to say "the thing matching this template should have these properties", instead of convoluted ways to turn off templates under certain circumstances. * coroutines are very half-baked, but when combined with executors (which will hopefully come in 23) it will really be useful I think. The stackless nature makes them hard to reason about, but trying to add stackful coroutines would likely be a non-starter; it would require a lot of runtime support and modifications that would either require a lot of performance overhead OR backward-compat difficulties.
That said, unless you want to actually use it to DO something specific (e.g. make a game, work at a specific company), Rust or similar languages are probably more pleasant experiences. Without a standardized build tool with sane defaults, it's hard to just play around with things in a fun way. Trying to figure out how CMake + Conan works will take beginners at least a day in my experience, and the lack of a solid template "good defaults, applicable most places but easily changeable" for the build system + dependency system makes things a bit tedious to just try things out.
https://stackoverflow.com/questions/636829/difference-betwee...
Is learning modern C++ worth the effort in 2021? I know classic c++, but don't really use it anymore.
> Is learning modern C++ worth the effort in 2021? (Hopping onto this topic,) I wonder, what are the right resources for properly diving into the modern C++? Are there books that are up to date? Tutorials? What has worked for HNs the best?
Is learning modern C++ worth the effort in 2021? I know classic c++, but don't really use it anymore.
I would say the experience is about what you would expect. There are some things that are great, that are cleaned up and more consistent. There are more conveniences. But then you run into weird edge cases / quirks, or a cascade of subtle compile errors, and just use a macro instead.
I'm writing a garbage collector and there are a bunch of things where it helps over C, but also a bunch of areas where it falls short. In summary, C++ is still great and frustrating at the same time. If anything that property seems to have increased over time: It's even more great and even more frustrating than it ever was :) Coroutines look like another example of that.
Some notes: - C++20 coroutines are stackless , meaning that multiple coroutines will share a single OS thread stack. This is non-obvious when you first look in to them them because coroutines look just like functions. The compiler does all the work of ensuring your local variables are captured and allocated as part of the coroutine yield context, but these yield contexts are not stack frames . Every coroutine you inv…
* calling into the coroutine from the caller uses the caller's stack (i.e. it just pushes on another stack frame). * the lack of a coroutine stack ("stackful" coroutine) means that the coroutine can only "yield" a value from a single method; it cannot call a function F, and then have F yield back to the original coroutine's caller. * In other words: you can think of it like a "coroutine with one stack frame for coroutine yielding semantics"
The compiler does some magic to slice up the coroutine into segments (between co_ statements) and stores state that must persist between these segments in a coroutine frame (in addition to the "slice" that the coroutine should continue at once it is called again).
The real tricky part is the lack of library support. From what I've seen, it seems like a naming convention is all that defines what various coroutine functions are, e.g. `promise` or `promise_type`. This is very much like iterators, which can be written via structural subtyping: anything that has the special static type values and/or methods can be used as one.
void main() does not exactly inspire confidence. https://stackoverflow.com/questions/636829/difference-betwee...