> It at least feels more like go, syntax-wise, than most, except for the num part, which seems like an afterthought.
It is an afterthought. It wasn't in the original proposal and was invented as a way to enable functions like Min, Max, and so on. But I realized that it actually enables many cool things like various generic math structures, vectors, matrices to work with arbitrary numeric types. It is a special case, but if you try and make it general, you end up with some sort of contracts, which may or may not be what you want, but is what I've been trying to avoid here. On Mon, Jun 3, 2019, 16:57 Martin Schnabel <m...@mb0.org> wrote: > I agree. That is a good point. I consider arrays an edge case. Although > still important, it will probably not be all too common. So the extra > verbosity should not be a problem. > > I am happy you generally agree and think these minor tweaks can make a > big difference for the roll-out of the proposed feature, if accepted. > > I also think, that this is one of the better proposals. It at least > feels more like go, syntax-wise, than most, except for the num part, > which seems like an afterthought. > > Again thank you for your work exploring this! > > Best regards > Marin > > On 03.06.19 15:49, Michal Strba wrote: > > 'const' could be fine too. I guess this is mostly a matter of personal > > preference. > > > > Regarding the array length syntax. It does require qualifying for two > > reasons: > > > > 1. Unnamed arguments. > > 2. Using 'gen' (or 'type', 'const') makes it easy to say "gen is not > > allowed in the return types", which is an important rule. Without > > qualification, this rule would be hard to express. > > > > On Mon, Jun 3, 2019, 15:26 Martin Schnabel <m...@mb0.org > > <mailto:m...@mb0.org>> wrote: > > > > Hi Michal, > > > > I would argue that the 'const' keyword would by more correct. Because > > the array length is and needs to be constant anyway. And it has > > currently no valid meaning in a parameter list, just like with > > the 'type' keyword. However i would argue that the array length, if > > written as part of the array syntax, as in '[n]elem' does not need an > > explicit keyword qualifier, because - again - it's unambiguous in the > > parameter context. Would you agree? > > > > Best regards > > Martin > > > > On 03.06.19 14:20, Michal Strba wrote: > > > Hi Martin. > > > > > > The proposal adds types as "values", but not really. You can only > > accept > > > a type to a function, but you cannot return a type. That makes the > > > system far from a dependent type system, even with the support for > > > generic array lengths. > > > > > > Being able to return types from functions and use those functions > in > > > types is what brings all the power (and complexity) of dependent > > typing, > > > but what I proposed is just a simple system for explicit type > > anotation > > > directly in the function signature. > > > > > > Regarding the 'gen' keyword, I chose it because I propose not only > > > generic types, but also generic array lengths. But you are right > > that > > > using 'type' would probably be better. Do you think that using the > > > 'type' keyword also in the context of generic array lengths would > > be fine? > > > > > > On Mon, Jun 3, 2019, 12:53 Martin Schnabel <m...@mb0.org > > <mailto:m...@mb0.org> > > > <mailto:m...@mb0.org <mailto:m...@mb0.org>>> wrote: > > > > > > Hi, > > > > > > is my impression correct, that this proposal adds types as > > values to > > > the > > > language? It's seems like it does the section 'Unnamed generic > > > arguments'. That by itself would go a long way and warrants > some > > > discussion, I'd say. > > > > > > If so, then why use a new keyword 'gen'? Why not 'type' > itself. > > > It would have some symmetry with how the func and struct > > keywords are > > > used for closures and unnamed structs. The 'type' keyword has > no > > > possible meaning in the parameter list currently. > > > > > > I use the 'gen' keyword a lot as identifier, mostly for > > generators > > > and generated code. While nobody can claim to use 'type'. > > This would > > > make converting code so much easier, if this proposal is > > accepted. > > > > > > Just a though. Please tell me whether this would be possible. > > > > > > Thanks for your work, it's much appreciated. > > > Martin > > > > > > > > > On 30.05.19 14:08, Michal Strba wrote: > > > > Hi Gophers! :) > > > > > > > > I've been thinking about generics in Go 2 ever since the > > original > > > > contracts proposal and few days ago, ideas finally > > clicked. One > > > of the > > > > main things about this proposal is that it deliberately > > omits the > > > > ability to restrict the set of types a function can work > with. > > > This is a > > > > limitation, but I hope to convince you that we can still > > do a vast > > > > majority of the things we were missing, when we were > missing > > > generics. > > > > > > > > I'd love to share my proposal with you and engage in a > > good faith > > > > conversation. > > > > > > > > Link to the proposal. > > > > > > <https://gist.github.com/faiface/e5f035f46e88e96231c670abf8cab63f> > > > > > > > > Here's what the proposal covers: > > > > > > > > 1. Syntax of a new gen keyword. > > > > 2. Generic functions. > > > > 3. Unnamed generic arguments (a.k.a. a way to gve a type > > to the > > > built-in > > > > newfunction). > > > > 4. Semantics of generic values (ability to use them as map > > keys, > > > ...). > > > > 5. Generic array lengths. > > > > 6. Reflection and interface{}. > > > > 7. Generic types (with two examples: Listand Matrix). > > > > 8. Generic methods and their limitations due to reflection. > > > > 9. Generic interfaces. > > > > 10. List of things this proposal can't do. > > > > > > > > Thanks, > > > > faiface > > > > > > > > -- > > > > You received this message because you are subscribed to > > the Google > > > > Groups "golang-nuts" group. > > > > To unsubscribe from this group and stop receiving emails > > from it, > > > send > > > > an email to golang-nuts+unsubscr...@googlegroups.com > > <mailto:golang-nuts%2bunsubscr...@googlegroups.com> > > > <mailto:golang-nuts%2bunsubscr...@googlegroups.com > > <mailto:golang-nuts%252bunsubscr...@googlegroups.com>> > > > > <mailto:golang-nuts+unsubscr...@googlegroups.com > > <mailto:golang-nuts%2bunsubscr...@googlegroups.com> > > > <mailto:golang-nuts%2bunsubscr...@googlegroups.com > > <mailto:golang-nuts%252bunsubscr...@googlegroups.com>>>. > > > > To view this discussion on the web visit > > > > > > > > > > https://groups.google.com/d/msgid/golang-nuts/6f5f0785-93f7-475a-991c-fc919c5e6730%40googlegroups.com > > > > > > > > > > > > < > https://groups.google.com/d/msgid/golang-nuts/6f5f0785-93f7-475a-991c-fc919c5e6730%40googlegroups.com?utm_medium=email&utm_source=footer > >. > > > > For more options, visit https://groups.google.com/d/optout > . > > > > > > -- > > > You received this message because you are subscribed to the > > Google > > > Groups "golang-nuts" group. > > > To unsubscribe from this group and stop receiving emails from > it, > > > send an email to golang-nuts+unsubscr...@googlegroups.com > > <mailto:golang-nuts%2bunsubscr...@googlegroups.com> > > > <mailto:golang-nuts%2bunsubscr...@googlegroups.com > > <mailto:golang-nuts%252bunsubscr...@googlegroups.com>>. > > > To view this discussion on the web visit > > > > > > https://groups.google.com/d/msgid/golang-nuts/739d147e-162d-14fc-a13a-9e7962f074e2%40mb0.org > . > > > For more options, visit https://groups.google.com/d/optout. > > > > > > -- > > > You received this message because you are subscribed to the Google > > > Groups "golang-nuts" group. > > > To unsubscribe from this group and stop receiving emails from it, > > send > > > an email to golang-nuts+unsubscr...@googlegroups.com > > <mailto:golang-nuts%2bunsubscr...@googlegroups.com> > > > <mailto:golang-nuts+unsubscr...@googlegroups.com > > <mailto:golang-nuts%2bunsubscr...@googlegroups.com>>. > > > To view this discussion on the web visit > > > > > > https://groups.google.com/d/msgid/golang-nuts/CAO6k0ut8W8STeA6_AadA9FbL7HxkVimKMfMT3bTBtxDyP1N5_w%40mail.gmail.com > > > > > > > < > https://groups.google.com/d/msgid/golang-nuts/CAO6k0ut8W8STeA6_AadA9FbL7HxkVimKMfMT3bTBtxDyP1N5_w%40mail.gmail.com?utm_medium=email&utm_source=footer > >. > > > For more options, visit https://groups.google.com/d/optout. > > > > -- > > You received this message because you are subscribed to the Google > > Groups "golang-nuts" group. > > To unsubscribe from this group and stop receiving emails from it, > > send an email to golang-nuts+unsubscr...@googlegroups.com > > <mailto:golang-nuts%2bunsubscr...@googlegroups.com>. > > To view this discussion on the web visit > > > https://groups.google.com/d/msgid/golang-nuts/068a6b44-4c52-73fc-9ac7-fe46b4cdbe1d%40mb0.org > . > > For more options, visit https://groups.google.com/d/optout. > > > > -- > > You received this message because you are subscribed to the Google > > Groups "golang-nuts" group. > > To unsubscribe from this group and stop receiving emails from it, send > > an email to golang-nuts+unsubscr...@googlegroups.com > > <mailto:golang-nuts+unsubscr...@googlegroups.com>. > > To view this discussion on the web visit > > > https://groups.google.com/d/msgid/golang-nuts/CAO6k0usVH6GMsqu%2BpDJ%2BOfeTnF0XDZq-RK_DKW5kxXRkEHsUmA%40mail.gmail.com > > < > https://groups.google.com/d/msgid/golang-nuts/CAO6k0usVH6GMsqu%2BpDJ%2BOfeTnF0XDZq-RK_DKW5kxXRkEHsUmA%40mail.gmail.com?utm_medium=email&utm_source=footer > >. > > For more options, visit https://groups.google.com/d/optout. > > -- > You received this message because you are subscribed to the Google Groups > "golang-nuts" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to golang-nuts+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/golang-nuts/11395c55-4cd4-7c35-2f39-77e49b28799a%40mb0.org > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/CAO6k0us9i_nhrGRgsQmcjBbavYZanq9Qycpg5uAyqOep%3DouNpA%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
