5 ms·

Go is an opinionated language. Go people would just tell you to write the loop; that's what it's there for.

jlgreco 14y ago
To be clear, generics seems to be one thing that Go isn't actually opinionated on. As I understand it, they are open to including generics in future versions of the language, but only if the implementation is elegant.
- _ak 14y ago
  Well, as far as I understand, that implementation would need to overcome the Generic Dilemma as described by Russ Cox: http://research.swtch.com/generic http://research.swtch.com/generic So far, the Go team decided to go for approach #1.
  - maaku 14y ago
    Option #3 is unfairly presented. There is no reason a language couldn't implicitly box every type, but automatically create efficient specializations for (some of) the types actually used. You can have your cake and eat it too. Of course, it's not easy to write such static optimizations. But it is, in principle, possible, and the sort of thing you only need write once.
    - dualogy 14y ago
      > But it is, in principle, possible, and the sort of thing you only need write once. Well Go is open source so "someone" would just have to write, test and submit a CL / patch... ;-)
  - masklinn 14y ago
    > So far, the Go team decided to go for approach #1. Except where they personally really wanted parametric polymorphic collections so they baked them as special case into the runtime, of course (map, chan, …)
  - codeflo 14y ago
    In a sense, they went for #3 (auto-boxing) without the syntactic sugar. Casting int to interface {} has a similar overhead to boxing in Java.
jerf 14y ago
The loop was a trivial example. Less trivial examples are not possible either. For instance, I'd like to write a function that takes in a channel and returns a (directional) channel that has been turned asynchronous, by running a goroutine that manages a queue and doing some other things above and beyond what a merely buffered channel does (emulating Erlang's way of managing async messages with backoff timeouts), but I can't do that correctly and safely. I haven't completely written this function in fact but it's certainly at least 20 lines. I'm making a list of the things that I tried to do in the language, then couldn't; I'm up to four right now, each of which are not trivial examples, but are instances of code that I must repeat because I can not refactor it. This is not a plus. (My list is at home and I'm not, and I'm sort of saving it for a blog post anyhow, but this is representative; not killer, but the issues compound as the program gets large.) Mind you, I know the language is young, etc etc, and I support the idea of doing it right rather than doing it sooner, nor am I attached to "generics" as the only possible solution. However, there is a real problem here for refactorability, and I would not want the Go community to build too much of a metaphorical callous around this issue and get to the point where they just reflexively respond with annoyance. There is a problem here.
- zemo 14y ago
  >For instance, I'd like to write a function that takes in a channel and returns a channel that has been turned asynchronous, by running a goroutine that manages a queue and doing some other things above and beyond what a merely buffered channel does, but I can't do that correctly and safely. see here: http://gowithconfidence.tumblr.com/post/31426832143/stacked-channels http://gowithconfidence.tumblr.com/post/31426832143/stacked-... the trick is to make a channel of buffer size 1, then when adding to it, simultaneously try to read and write from that channel using a select statement. Only one will ever be ready. You could also do something similar really horribly with interface{} but that's almost always a code smell: https://gist.github.com/jordanorelli/3668150 https://gist.github.com/jordanorelli/3668150 I probably wouldn't do that in production code. Either way, generics in Go remains an open question.
  - jerf 14y ago
    That's simpler that what Erlang does (you need some code for the time backoff, and while I think Go can do it it is inherently the sort of code that ends up a complicated mess of cases that, if I could lock it behind a function, would be very well abstracted away for the user), but it is the basic idea. The problem is, you have to copy & paste those lines of code for every type you want to do that with; you can't vary that code on "Thing". In this case the fact I'd have to use interface{} isn't a code smell, it's a language smell. Looking in two different "directions" from Go, that's trivial to implement as a single Thing-agnostic function in the weaker-type system Python (gevent queues have similar enough semantics for this to be a fair comparison), and it's trivial in stronger-type system Haskell (also similar enough semantics with TChan to be fair). Also I note you did not return the chan for the user to do with as they like, abstracting out the mechanics from the task, but have a hard-coded "join" function in there. You can easily take in a function to "do something", but you won't be able to do anything with the resulting value, not even return it, unless via inteface{}. (Which makes me cringe every time I type it.) Again, to be clear, I'm not trying to dump on Go here; there's a lot of things to like about it, especially its infrastructure. But this is by far my biggest pain point with it personally. YMMV.

To be clear, generics seems to be one thing that Go isn't actually opinionated on. As I understand it, they are open to including generics in future versions of the language, but only if the implementation is elegant.

_ak 14y ago
Well, as far as I understand, that implementation would need to overcome the Generic Dilemma as described by Russ Cox: http://research.swtch.com/generic http://research.swtch.com/generic So far, the Go team decided to go for approach #1.
- maaku 14y ago
  Option #3 is unfairly presented. There is no reason a language couldn't implicitly box every type, but automatically create efficient specializations for (some of) the types actually used. You can have your cake and eat it too. Of course, it's not easy to write such static optimizations. But it is, in principle, possible, and the sort of thing you only need write once.
  - dualogy 14y ago
    > But it is, in principle, possible, and the sort of thing you only need write once. Well Go is open source so "someone" would just have to write, test and submit a CL / patch... ;-)
- masklinn 14y ago
  > So far, the Go team decided to go for approach #1. Except where they personally really wanted parametric polymorphic collections so they baked them as special case into the runtime, of course (map, chan, …)
- codeflo 14y ago
  In a sense, they went for #3 (auto-boxing) without the syntactic sugar. Casting int to interface {} has a similar overhead to boxing in Java.

jerf 14y ago

The loop was a trivial example. Less trivial examples are not possible either. For instance, I'd like to write a function that takes in a channel and returns a (directional) channel that has been turned asynchronous, by running a goroutine that manages a queue and doing some other things above and beyond what a merely buffered channel does (emulating Erlang's way of managing async messages with backoff timeouts), but I can't do that correctly and safely. I haven't completely written this function in fact but it's certainly at least 20 lines. I'm making a list of the things that I tried to do in the language, then couldn't; I'm up to four right now, each of which are not trivial examples, but are instances of code that I must repeat because I can not refactor it. This is not a plus. (My list is at home and I'm not, and I'm sort of saving it for a blog post anyhow, but this is representative; not killer, but the issues compound as the program gets large.) Mind you, I know the language is young, etc etc, and I support the idea of doing it right rather than doing it sooner, nor am I attached to "generics" as the only possible solution. However, there is a real problem here for refactorability, and I would not want the Go community to build too much of a metaphorical callous around this issue and get to the point where they just reflexively respond with annoyance. There is a problem here.

zemo 14y ago
>For instance, I'd like to write a function that takes in a channel and returns a channel that has been turned asynchronous, by running a goroutine that manages a queue and doing some other things above and beyond what a merely buffered channel does, but I can't do that correctly and safely. see here: http://gowithconfidence.tumblr.com/post/31426832143/stacked-channels http://gowithconfidence.tumblr.com/post/31426832143/stacked-... the trick is to make a channel of buffer size 1, then when adding to it, simultaneously try to read and write from that channel using a select statement. Only one will ever be ready. You could also do something similar really horribly with interface{} but that's almost always a code smell: https://gist.github.com/jordanorelli/3668150 https://gist.github.com/jordanorelli/3668150 I probably wouldn't do that in production code. Either way, generics in Go remains an open question.
- jerf 14y ago
  That's simpler that what Erlang does (you need some code for the time backoff, and while I think Go can do it it is inherently the sort of code that ends up a complicated mess of cases that, if I could lock it behind a function, would be very well abstracted away for the user), but it is the basic idea. The problem is, you have to copy & paste those lines of code for every type you want to do that with; you can't vary that code on "Thing". In this case the fact I'd have to use interface{} isn't a code smell, it's a language smell. Looking in two different "directions" from Go, that's trivial to implement as a single Thing-agnostic function in the weaker-type system Python (gevent queues have similar enough semantics for this to be a fair comparison), and it's trivial in stronger-type system Haskell (also similar enough semantics with TChan to be fair). Also I note you did not return the chan for the user to do with as they like, abstracting out the mechanics from the task, but have a hard-coded "join" function in there. You can easily take in a function to "do something", but you won't be able to do anything with the resulting value, not even return it, unless via inteface{}. (Which makes me cringe every time I type it.) Again, to be clear, I'm not trying to dump on Go here; there's a lot of things to like about it, especially its infrastructure. But this is by far my biggest pain point with it personally. YMMV.