On Sun, Sep 9, 2018 at 9:35 AM Ian Lance Taylor <i...@golang.org> wrote:
> As I've said before, I would very much like to avoid adding many > different names to the language. Also, there are many different cases > to handle. Consider type conversions, for example; how do you express > that you want to have two types, with one being convertible to the > other? FWIW, in my pseudo-interface description <https://blog.merovius.de/2018/09/05/scrapping_contracts.html>, this *could* be solved by having two parametric pseudo-interfaces convertibleTo(T) and convertibleFrom(T) and then writing, e.g. type Floaty interface { convertibleTo(float64) convertibleFrom(float64) } func Sin(type T Floaty) (v T) T { return T(math.Sin(float64(v)) } func main() { fmt.Println(Sin(math.Pi)) fmt.Println(Sin(float64(math.Pi)) fmt.Println(Sin(uint64(0)) } This works because pseudo-interfaces aren't *really* interfaces - i.e. don't rely on Methods - so there is no clashing. Now, you said before that you'd like to avoid people having to learn a bunch of names to write generic code and that's a fair requirement¹ which of course makes this not work. But without that requirement, I still believe that interfaces-as-constraints and pseudo-interfaces for builtin operations would be able to address all use cases that contracts just as clearly and concisely. Sorry, I broke my promise… [1] though I don't understand why. And I'm arguing in my post that people still have to learn just as much - just learn them as cargo-culted obscure contracts instead of words. > I encourage you to work through the various examples in the > design draft and consider how to write them. > > Ian > > -- > 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. > 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. For more options, visit https://groups.google.com/d/optout.
