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Wow this got really long. I was one of the coauthors for a reflection proposal (N3340) over a dozen years ago. Implementing compile-time reflection is honestl

Wow this got really long. I was one of the coauthors for a reflection proposal (N3340) over a dozen years ago. Implementing compile-time reflection is honestly trivial - you basically transfer data from the symbol table on-demand into template specializations. It was roughly 1500 LOC to modify g++ to do it. Looking at the examples (https://isocpp.org/files/papers/P2996R4.html#examples https://isocpp.org/files/papers/P2996R4.html#examples) what really stands out is the direct integration of type-syntax into the language. It fits in with a certain token-substitution way that connects back to templates. It also replaces some of the uglier operators (typeof?). I hope it goes int! During the language's stagnation I left for a while, perhaps it'll be competitive again soon.

stiglitz 2y ago
By ”stagnation” do you mean “not getting new features”?
- deleted 2y ago
  [deleted]
- vlovich123 2y ago
  N3340 is from 2011. Prior to c++11 they had failed to deliver major changes to the language. And arguably the disfunction is still there where big ideas get destroyed in committee (reflection) or take forever and come out half-baked (modules).
  - rerdavies 2y ago
    Speaking of half-baked, did continuations get fixed?
- CuriousCosmic 2y ago
  C++ has gotten a ton of quality of life features with each update. The issue is less that new features aren't coming and more that new features bake through countless iterations of proposals for close to or often over a decade until everyone in WG21 is happy. So it's not that we aren't getting features. They are coming quite fast and people regularly complain that new C++ has too many things for them to learn and keep up with. The issue is that those are the same features everyone has been asking for for over a decade so the people that really care found workarounds and eventually move over to the new std way of doing things when they can while everyone else continues waiting for that one feature they really care about.
  - adrianN 2y ago
    The people complaining and the people asking for features need not be overlapping sets.
  - physicsguy 2y ago
    > the people that really care found workarounds Or stopped writing C++, I'd consider myself one of these for many use cases I used to use it for.
    - chipdart 2y ago
      > Or stopped writing C++, I'd consider myself one of these for many use cases I used to use it for. Some use cases like GUI programming sound like they are better addressed by specialized tech stacks. Nevertheless, either you're talking about greenfield projects or you are hard pressed to find a justification to rewrite a project in another framework. Claiming you stopped writing C++ doesn't fit the bulk of the experience of anyone maintaining C++ projects.
      - PathOfEclipse 2y ago
        My experience maintaining old codebases is that you are just as hard-pressed to find a justification to write code to use new language features, or even to take the time to upgrade the language and compiler version. Most often you just continue writing code in the same style as the rest of the code base using an old version of the language and runtime.
        chipdart 2y ago
        > My experience maintaining old codebases is that you are just as hard-pressed to find a justification to write code to use new language features, or even to take the time to upgrade the language and compiler version. That's perfectly fine. You should only pay for what you use. Your average project, however, consumes dependencies and needs to keep them updated. Just because the code you write doesn't use them that doesn't mean your dependencies don't. So everyone still benefits with each release of C++ even if the are not using fancy features.
cb321 2y ago
I think another good example might be extracting function signatures (parameter names & types, default values -- if any) at compile-time for various purposes.

stiglitz 2y ago

By ”stagnation” do you mean “not getting new features”?

deleted 2y ago
[deleted]
vlovich123 2y ago
N3340 is from 2011. Prior to c++11 they had failed to deliver major changes to the language. And arguably the disfunction is still there where big ideas get destroyed in committee (reflection) or take forever and come out half-baked (modules).
- rerdavies 2y ago
  Speaking of half-baked, did continuations get fixed?
CuriousCosmic 2y ago
C++ has gotten a ton of quality of life features with each update. The issue is less that new features aren't coming and more that new features bake through countless iterations of proposals for close to or often over a decade until everyone in WG21 is happy. So it's not that we aren't getting features. They are coming quite fast and people regularly complain that new C++ has too many things for them to learn and keep up with. The issue is that those are the same features everyone has been asking for for over a decade so the people that really care found workarounds and eventually move over to the new std way of doing things when they can while everyone else continues waiting for that one feature they really care about.
- adrianN 2y ago
  The people complaining and the people asking for features need not be overlapping sets.
- physicsguy 2y ago
  > the people that really care found workarounds Or stopped writing C++, I'd consider myself one of these for many use cases I used to use it for.
  - chipdart 2y ago
    > Or stopped writing C++, I'd consider myself one of these for many use cases I used to use it for. Some use cases like GUI programming sound like they are better addressed by specialized tech stacks. Nevertheless, either you're talking about greenfield projects or you are hard pressed to find a justification to rewrite a project in another framework. Claiming you stopped writing C++ doesn't fit the bulk of the experience of anyone maintaining C++ projects.
    - PathOfEclipse 2y ago
      My experience maintaining old codebases is that you are just as hard-pressed to find a justification to write code to use new language features, or even to take the time to upgrade the language and compiler version. Most often you just continue writing code in the same style as the rest of the code base using an old version of the language and runtime.
      - chipdart 2y ago
        > My experience maintaining old codebases is that you are just as hard-pressed to find a justification to write code to use new language features, or even to take the time to upgrade the language and compiler version. That's perfectly fine. You should only pay for what you use. Your average project, however, consumes dependencies and needs to keep them updated. Just because the code you write doesn't use them that doesn't mean your dependencies don't. So everyone still benefits with each release of C++ even if the are not using fancy features.

cb321 2y ago

I think another good example might be extracting function signatures (parameter names & types, default values -- if any) at compile-time for various purposes.