If I understand correctly, this question is specifically addressed by the design draft: https://go.googlesource.com/proposal/+/refs/heads/master/design/go2draft-type-parameters.md#why-not-put-type-parameters-on-packages
On Wednesday, January 20, 2021 at 10:22:19 AM UTC-5 atd...@gmail.com wrote: > Hello, > > It' has probably been discussed somewhere but I am curious about what > might have been the issues when considering an implementation of generics > that would parameterized packages? > > The rationale being that usually, packages have a non-mutable interface > for the user and are the ompilation unit if I'm not mistaken. So why not > just relax the interface exposed by a package and allow for package-wide > type specialization? > > In terms of pure parametric polymorphism, having packages with a mutable > interface in terms of types (via mutation of type aliases for instance) > would just be the next iteration. It may require a little bit more from the > build tool but the type checking would not have to change I think. The > constraints on the parameter would stem implicitly from the code within a > package in terms of operations used and interfaces being implemented. > > I would expect such "parameterized" packages to be rare, non-pervasive if > not for the simple fact that most parameterized package would mostly be > able to import other generic packages since they would be defined with > abstract types. The compiler may still want to insure that the constraints > make sense throughout the dependency tree of generic imports incrementally > but I don't think that that would be a huge problem. > > I think that it could be something orthogonal to the design of type > constraintd, notably type Lists, that are anyway highly desirable imo but > more so to constrain interfaces to a finite set of types ( as a way to have > union types, enums, sumtypes or whatnot). > > > > -- 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/d82f7ae9-40e2-484f-ae41-fcd597f47a0dn%40googlegroups.com.
