Feedback after 6 months developing in Cpp2

[MatthieuHernandez]

Hello everyone 👋,
I apologize in advance, this post is a bit long. I am writing this post to share my experience, hoping that it will be of interest to some people. I would also be curious to hear your own feedback and opinions on development in Cpp2 to see if we share similar perspectives or if your experience has been different.

Introduction to myself and my project

First of all, I've been coding in C++ for about 10 years .I'm not the best, but I'm doing pretty well.
Passionate about the go game, I embarked on the idea of creating a Go AI.
Since I already had my own deep learning library in C++20, I thought this project would be a good opportunity to test cppfront.

In the end, the AI couldn't learn to play properly (even if something resembling go seems to be emerging), but I managed to create a Qt application to play go game, set up an AI, and train it by having it play games against itself in a loop. The Qt part is in C++, but all of the game engine, rule implementation, AI model definition, and training are entirely in Cpp2.

Here is the GitHub project repository: https://github.com/MatthieuHernandez/gopp2
Feel free to take a look at the project and make suggestions on the Cpp2 section, as I'm not sure I've done everything correctly.

Now let's get to the point: what did I think of Cpp2?

I made a list of pros and cons. Tell me if you agree with it.

PROS:

• The general syntax is quite pleasant once you get the hang of it.
• The in, out, inout parameter system is, in my opinion, the language's greatest strength.
• The keyword as is really handy.
• The operator= for all constructors is a very good idea.
• Translation to C++ via cppfront is simple and works well.
• No problems encountered with tools: whether Clang, GCC, CMake, VS Code, etc.

CONS:

• The biggest problem with the language at the moment is that you already need to be very good at C++ to code in Cpp2. Balancing between cppfront errors and C++ compiler errors is complicated at first, especially since Cpp2 makes some compiler messages hard to understand, as they apply to the code generated by cppfront.
• Integrating Qt into Cpp2 code was very painful because cppfront doesn't generate any *.cpp files, which makes it very complicated when you have to separate the declaration from the implementation. I managed to get around this with the -pure-cpp2 option, which generates a *.h file for the declaration and a *.hpp file for the implementation.
• I had major issues using enums, so I had to use classes instead.
• Some C++ features are missing: Conditional operator, switch case, and probably others.
• I had cppfront errors for some inout variables not used in recursive functions, which I had to work around by adding assertions.
• I had to put a try catch in a method written in C++ because Cpp2 does not support this feature.
• I haven't been able to get unique_ptr to work in Cpp2 in certain cases, and I can't remember exactly why. I switched to shared_ptr instead.
• I miss Clangd, Clang-Tidy, and Clang-Format.

In conclusion, I really enjoyed learning Cpp2 😊 The language is still lacking in maturity, but that's normal at this stage.
On the other hand, I would have made much faster progress on my project if I had done it in C++ rather than Cpp2.
I spent far too much time trying to figure out how to fix or work around Cpp2 issues that I would never have had in C++ or that I would have been able to solve instantly.

[rrrlasse]

I think that tooling (clang-tidy, etc) and error messages are because cppfront is a playground for a new syntax and not meant for actual use.

[LT2H]

I'm building something with cppfront too. As for Clang-Format, you can use Cpp2-supported version by Johel Ernesto Guerrero Peña, it works pretty well.

[MaxSagebaum]

Nice feedback. There is also a prototype for a language server. https://github.com/vanceism7/ls-cpp2

Everything is there: But still in prototype state. 😆