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D has been around for 21 years. It has had a compiler in the gcc project (gdc) for four years. It debugs easily enough under gdb. Several editors support D s

D has been around for 21 years. It has had a compiler in the gcc project (gdc) for four years. It debugs easily enough under gdb. Several editors support D syntax (including geany and vscode). It has quite a few libraries (though its interoperability with C libraries has muted native D library development somewhat), centralized at https://code.dlang.org/ https://code.dlang.org/ Are there specific parts of the ecosystem you worry about not being mature? As for it being a bit esoteric, yes, it's not a very widely known language, though I'm not sure why. I fell in love with it in 2018, and it has thoroughly spoiled me for writing C.

Conscat 4y ago
One big issue with D compared to Rust for performance-oriented code is the lack of move semantics. Rust and C++ idiomatically almost never rely on copy-on-write, whereas D so far has a lot of it. I'm not sure how much this matters for kernel modules, but I imagine that it is something users would consider. I had seen some proposals for move semantics in D, so for all I know this is under works right now.
- destructionator 4y ago
  D rarely has copy on write. It will just plain copy certain types on assignment though so perhaps that's what you meant.
- p0nce 4y ago
  C++ code has a lot of copies actually.
vlovich123 4y ago
Maturity in a systems programming sense is different. Rust had a lot of effort pored (and still going) into the nostd variant to be used in bare metal applications like microcontrollers and kernels. Does D have that same level of formalism? On a more serious note, I’m skeptical D would take. It seems like Rust has captured mind share and already has ongoing substantial work integrating it into the kernel (+ it’s the first and only non C language in kernel mainline). Given that context, I don’t see the motivation that works spur a similar level of support from kernel maintainers.
- spookie 4y ago
  I'm sorry, but shouldn't we critique Dlang itself instead of the constant comparisons with Rust? Dlang has had significant work poured into it, and the project has delivered a quality language with safety in mind. I don't mean to be defensive, but these threads always seem to ask the same question, it's boring at this point.
  - vlovich123 4y ago
    I think it's fair game to discuss Rust in this context since there's a major effort underway to support writing in-kernel drivers in Rust. Unless you think the kernel will be a bazaar of languages, then it's useful to think about which language is the most likely to "win".
    - pjmlp 4y ago
      There are other OSes out there where D could eventually make a mark. Naturally the whole issue is that there is no big movement regarding writing OSes in D for that to matter anyway. Better luck using TinyGo, Java, .NET or Oberon in bare metal workloads (where runtime plays the OS role), as there are a couple of products for them, than D.
    - spookie 4y ago
      I think it would be of value, to a degree, if the kernel supported multiple languages. As some languages are better suited for some tasks. This implies comparing them, so I understand your point now.
- ttkciar 4y ago
  > Rust had a lot of effort pored (and still going) into the nostd variant to be used in bare metal applications like microcontrollers and kernels. D has had "dcompute" since 2017, for native execution on GPUs and other accelerators. People have been writing D for microcontrollers since at least 2011, possibly earlier. D is fairly mature in the systems space. > I’m skeptical D would take. Maybe, maybe not. Some languages "click" better than others for individual programmers. It's good to have options. > it’s the first and only non C language in kernel mainline Do you foresee it being the only non-C language used in the kernel forever?

Conscat 4y ago

One big issue with D compared to Rust for performance-oriented code is the lack of move semantics. Rust and C++ idiomatically almost never rely on copy-on-write, whereas D so far has a lot of it. I'm not sure how much this matters for kernel modules, but I imagine that it is something users would consider. I had seen some proposals for move semantics in D, so for all I know this is under works right now.

destructionator 4y ago
D rarely has copy on write. It will just plain copy certain types on assignment though so perhaps that's what you meant.
p0nce 4y ago
C++ code has a lot of copies actually.

vlovich123 4y ago

Maturity in a systems programming sense is different. Rust had a lot of effort pored (and still going) into the nostd variant to be used in bare metal applications like microcontrollers and kernels. Does D have that same level of formalism? On a more serious note, I’m skeptical D would take. It seems like Rust has captured mind share and already has ongoing substantial work integrating it into the kernel (+ it’s the first and only non C language in kernel mainline). Given that context, I don’t see the motivation that works spur a similar level of support from kernel maintainers.

spookie 4y ago
I'm sorry, but shouldn't we critique Dlang itself instead of the constant comparisons with Rust? Dlang has had significant work poured into it, and the project has delivered a quality language with safety in mind. I don't mean to be defensive, but these threads always seem to ask the same question, it's boring at this point.
- vlovich123 4y ago
  I think it's fair game to discuss Rust in this context since there's a major effort underway to support writing in-kernel drivers in Rust. Unless you think the kernel will be a bazaar of languages, then it's useful to think about which language is the most likely to "win".
  - pjmlp 4y ago
    There are other OSes out there where D could eventually make a mark. Naturally the whole issue is that there is no big movement regarding writing OSes in D for that to matter anyway. Better luck using TinyGo, Java, .NET or Oberon in bare metal workloads (where runtime plays the OS role), as there are a couple of products for them, than D.
  - spookie 4y ago
    I think it would be of value, to a degree, if the kernel supported multiple languages. As some languages are better suited for some tasks. This implies comparing them, so I understand your point now.
ttkciar 4y ago
> Rust had a lot of effort pored (and still going) into the nostd variant to be used in bare metal applications like microcontrollers and kernels. D has had "dcompute" since 2017, for native execution on GPUs and other accelerators. People have been writing D for microcontrollers since at least 2011, possibly earlier. D is fairly mature in the systems space. > I’m skeptical D would take. Maybe, maybe not. Some languages "click" better than others for individual programmers. It's good to have options. > it’s the first and only non C language in kernel mainline Do you foresee it being the only non-C language used in the kernel forever?