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Yes, but Go has specificities that make difficult to directly use the scheme used by other languages: Go is AOT compiled (we can't use C# generics), Go favors c

Yes, but Go has specificities that make difficult to directly use the scheme used by other languages: Go is AOT compiled (we can't use C# generics), Go favors compilation speed (we can't use C++ template), Go lets the developer control memory layout with arrays and structs (we can't use OCaml generics), etc. Of course, Go should get inspiration from other languages, but adding generics is not easy as simply transposing another language implementation. There are multiple detailed proposals in the bug tracker that have failed for multiple reasons.

dbaupp 9y ago
Swift has essentially all the same constraints, and fretting about compilation speed with the C++ approach are hard to stomach given one of the widely-used replacement is equivalent: manually copy-pasting code, instead of letting the compiler do it. In any case, the truth of the complaint about generics isn't actually relevant here: the rebuttal is to "people complain about Go not reinventing enough", and they don't, as they (truthfully or otherwise) think it is ignoring already researched and widely-implemented solutions to the problem and complain about this (that is, the complaint is "uninventing", not "not enough reinventing").
- ngrilly 9y ago
  I didn't mention Swift and I should have. I agree it's close enough to Go to provide useful inspiration. But even Swift implementation of generics has its issues and tradeoffs. Look for example at this thread about "Compile-time generic specialization" in Swift: https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20170130/031466.html https://lists.swift.org/pipermail/swift-evolution/Week-of-Mo... Repeating that Go ignores "already researched and widely-implemented solutions" is getting old, really. Would you say that OCaml doesn't have shared memory multicore parallelism because it ignores already researched and widely-implemented solutions??? Would you say that Haskell garbage collector causes long runtime pauses because it ignores already researched and widely-implemented solutions??? The truth is that solving that kind of things is a lot more complex than just copy-paste the code from another language.
  - dbaupp 9y ago
    I'm... intimately familiar with generics in Swift. :) Like all systems it has trade-offs, but the decision it makes line up with the decisions you said Go wanted to also make. In any case, that specific concern doesn't apply to Go, since it doesn't have overloading. > Repeating that Go ignores "already researched and widely-implemented solutions" is getting old, really Sure, but that still isn't the point of this discussion: it's not what people should be doing, or the underlying truth, it's what people are doing in practice and they are complaining about the Go team seemingly ignoring the past 40 years of programming language development, not complaining that they're not inventive enough.
    - ngrilly 9y ago
      You're right about the issue I mentioned which is irrelevant since there is no overloading in Go. Thanks for pointing it out. I didn't know you worked on Rust and now on Swift :-) What strategy does Swift use to compile a generic function or method? Does it generate only one polymorphic version of the code, or multiple specialized versions for each expected parameter types (often called code specialization or monomorphization)?
      - dbaupp 9y ago
        One polymorphic version, like OCaml or Haskell, not specializing like C++ or Rust. The compiler can and does specialize functions as an optimization, but that's not necessary nor part of the semantic model.
        ngrilly 9y ago
        I always thought that generating one polymorphic version would be a better fit for Go than generating multiple specialized versions. It's interesting that Swift adopted this approach and confirms what you said earlier about Swift having essentially the same constraints as Go and being a good source of inspiration of Go. What's the status of Swift on Linux, to write web services and connect to databases?
pjmlp 9y ago
There are also CLU, Ada, Modula-2, Modula-3, Eiffel, Sather, BETA as possible inspirations for implementing generics, all the way back to 1976 (CLU). As for C#, people keep forgetting .NET always had a JIT/AOT compiler since version 1.0. Just because not everyone bothers to sign their applications and call NGEN at installation time, it doesn't mean it isn't there. Also Mono always supported AOT compilation, it is the way Xamarin works on iOS and the deployment story on Windows Store since it was introduced on Windows 8.
- ngrilly 9y ago
  I remember Mono with AOT compilation had some limitations regarding generics in the past, but maybe this has been solved since then.
  - pjmlp 9y ago
    Yes Mono has some limitations, but it isn't 100% like the iOS Xamarin compiler. http://www.mono-project.com/docs/advanced/aot/ http://www.mono-project.com/docs/advanced/aot/ In any case, a limited form of generics is better than not having any at all. They don't need to provide a turing complete implementation of generics, even a basic one like CLU had would already be an improvement. Using go generate feels like the old days, writing generic code in C and C++ with pre-processor tricks.
    - ngrilly 9y ago
      I agree. I hope the Go team will tackle this issue, when they are done with dependency management.

dbaupp 9y ago

Swift has essentially all the same constraints, and fretting about compilation speed with the C++ approach are hard to stomach given one of the widely-used replacement is equivalent: manually copy-pasting code, instead of letting the compiler do it. In any case, the truth of the complaint about generics isn't actually relevant here: the rebuttal is to "people complain about Go not reinventing enough", and they don't, as they (truthfully or otherwise) think it is ignoring already researched and widely-implemented solutions to the problem and complain about this (that is, the complaint is "uninventing", not "not enough reinventing").

ngrilly 9y ago
I didn't mention Swift and I should have. I agree it's close enough to Go to provide useful inspiration. But even Swift implementation of generics has its issues and tradeoffs. Look for example at this thread about "Compile-time generic specialization" in Swift: https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20170130/031466.html https://lists.swift.org/pipermail/swift-evolution/Week-of-Mo... Repeating that Go ignores "already researched and widely-implemented solutions" is getting old, really. Would you say that OCaml doesn't have shared memory multicore parallelism because it ignores already researched and widely-implemented solutions??? Would you say that Haskell garbage collector causes long runtime pauses because it ignores already researched and widely-implemented solutions??? The truth is that solving that kind of things is a lot more complex than just copy-paste the code from another language.
- dbaupp 9y ago
  I'm... intimately familiar with generics in Swift. :) Like all systems it has trade-offs, but the decision it makes line up with the decisions you said Go wanted to also make. In any case, that specific concern doesn't apply to Go, since it doesn't have overloading. > Repeating that Go ignores "already researched and widely-implemented solutions" is getting old, really Sure, but that still isn't the point of this discussion: it's not what people should be doing, or the underlying truth, it's what people are doing in practice and they are complaining about the Go team seemingly ignoring the past 40 years of programming language development, not complaining that they're not inventive enough.
  - ngrilly 9y ago
    You're right about the issue I mentioned which is irrelevant since there is no overloading in Go. Thanks for pointing it out. I didn't know you worked on Rust and now on Swift :-) What strategy does Swift use to compile a generic function or method? Does it generate only one polymorphic version of the code, or multiple specialized versions for each expected parameter types (often called code specialization or monomorphization)?
    - dbaupp 9y ago
      One polymorphic version, like OCaml or Haskell, not specializing like C++ or Rust. The compiler can and does specialize functions as an optimization, but that's not necessary nor part of the semantic model.
      - ngrilly 9y ago
        I always thought that generating one polymorphic version would be a better fit for Go than generating multiple specialized versions. It's interesting that Swift adopted this approach and confirms what you said earlier about Swift having essentially the same constraints as Go and being a good source of inspiration of Go. What's the status of Swift on Linux, to write web services and connect to databases?

pjmlp 9y ago

There are also CLU, Ada, Modula-2, Modula-3, Eiffel, Sather, BETA as possible inspirations for implementing generics, all the way back to 1976 (CLU). As for C#, people keep forgetting .NET always had a JIT/AOT compiler since version 1.0. Just because not everyone bothers to sign their applications and call NGEN at installation time, it doesn't mean it isn't there. Also Mono always supported AOT compilation, it is the way Xamarin works on iOS and the deployment story on Windows Store since it was introduced on Windows 8.

ngrilly 9y ago
I remember Mono with AOT compilation had some limitations regarding generics in the past, but maybe this has been solved since then.
- pjmlp 9y ago
  Yes Mono has some limitations, but it isn't 100% like the iOS Xamarin compiler. http://www.mono-project.com/docs/advanced/aot/ http://www.mono-project.com/docs/advanced/aot/ In any case, a limited form of generics is better than not having any at all. They don't need to provide a turing complete implementation of generics, even a basic one like CLU had would already be an improvement. Using go generate feels like the old days, writing generic code in C and C++ with pre-processor tricks.
  - ngrilly 9y ago
    I agree. I hope the Go team will tackle this issue, when they are done with dependency management.