Add C++ 20

[barnasm]

Please complete the following information:

• Name: C++
• Version: 20
• Release Note/Changelog: https://en.cppreference.com/w/cpp/compiler_support

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👍 reaction might help to get this request prioritized.

[Urfoex]

Probably still needs some time to mature.
From ~ half a year ago, the support of version 20 features in compilers is still lacking a bit…
#42 (comment)

Out of curiosity:
Which features are you looking for?

[barnasm]

Some of the new features in std may help us write more compact code that is easier to read. for example std :: ranges, std :: to_array, std :: span, std :: map :: contains, std :: vector :: erase etc. Maybe that doesn't seem like a big deal, but I'd like to practice, learn and take advantages of the latest available standards.

So I will ask the opposite question. Which lack of compiler functionality prevents us from adding C ++ 20 support?

[Urfoex]

Ranges can at least be used somewhat with ranges-v3 library:
#42

Yeah, such neat methods would be nice.
Doing latest C++ version, and then coming to some prior version, complaining that some things are not there, is always a little confusing. In such cases I just copy-paste the fitting old code.

Personally I would like to see the following still missing features:

• coroutines
• concepts
• modules
• ranges (usable via ranges-v3)
• text formatting (usable via fmt Add {fmt} for C++ #87)

But then again, for solving problems, they are not that much needed.

Also, currently Clang is used for compiling: #42 (comment)
With MSVC or GCC there would already be a bit more support.

All in all, definitively +1 for new version ^^

[kazk]

Which lack of compiler functionality prevents us from adding C ++ 20 support?

Technically, nothing prevents adding support (maybe the test framework need another patch, but haven't tried yet). I just don't want users to get confused and complain (e.g., "X is in C++20, but doesn't work on Codewars"). Unlike most of the languages with versions that describes the implementation, C++20 is a standard and compilers are still working on it. We show compiler name and version, but users won't look up the compiler support status.

That being said, we can add support sometime soon if C++ users think it's ready.

With MSVC or GCC there would already be a bit more support.

We can use GCC if necessary. I think Clang was chosen because of the better error messages many years ago. As far as I know, GCC got much better.

/cc @error256 @hobovsky

[wrazik]

Any update here?

As the compiler version is known, users can check support for a specific feature. C++ people are aware that C++20 is not fully supported in gcc & clang (MSVS is already feature-complete!)

C++20 changes significantly way of writing the code - concepts, ranges, coroutines. Algorithms will look totally different. C++20 is a must-have!

As already mentioned, it would be great to have ranges-v3 & fmtlib also available.

[kazk]

Any update here?

I'm waiting for feedback.

As already mentioned, it would be great to have ranges-v3 & fmtlib also available.

fmt and ranges-v3 are already supported.

[wrazik]

What feedback do you need? There is never too soon to upgrade the compiler :) Compiler support for C++20 features is available here: https://en.cppreference.com/w/cpp/compiler_support/20 . Gcc has better support for ranges so I would vote for switching to gcc. There is no significant difference in error readability nowadays.

I don't think you should wait till all features will be implemented. Missing stuff is rather minor, all game-changers (modules, ranges, concepts, couroutines) are there.

[hobovsky]

I am sorry, but I missed the notification that you mentioned me.

Unfortunately, as you probably noticed, my C++ skills are really rusty (I stopped doing professional C++ a couple of weeks before C++11 got published) and I am completely out of the loop when it comes to compilers, support matrices, most of modern features (modern as in C++11 and newer ;) ) so I have no strong opinion on whether C++20 is good to go or not.

The one thing I know I like about C++20 is formatting, improvements to containers (contains, yay!), and concepts (if I only wrap my mind around how to use them). However I'd definitely vote for C++20 if it'd mean anything better than Igloo ;)

There are two new members who are very active in area of C++ authoring, I could bring this topic to their attention and see what others think :)

[wrazik]

The difference between C++17 and C++20 is bigger than the difference between C++03 and C++11. It will really make a difference.

[wtlgo]

Hello, In my opinion, it would be better to wait a little bit more till compilers fully support C++20, but the current coverage by the most popular compilers is pretty enough to be useful. Though, I wouldn't for example use it in my personal projects yet.

[mere-human]

This issue is still relevant.
Now Clang has support for most of the C++20 features.
Using C++20 will allow to write more compact code using the best practices.
Switching from C++17 to C++20 we will not lose anything. The same C++17 code is still valid.
Clang C++20 status:
https://clang.llvm.org/cxx_status.html#cxx20
https://libcxx.llvm.org/Status/Cxx20.html