The word "elegant" comes to mind... Comments below. On Monday, 5 November 2018 21:47:46 UTC+2, Andy Balholm wrote: > > The concept of using operators to implement methods cross-pollinated in my > mind with Patrick’s “Go Generics with Adaptors” thought experiment and > produced this: > https://gist.github.com/andybalholm/acecba3acf57bf1254142dadce928890 > > Here is the core of the proposal (the gist of the gist?): > > Contracts > > In this proposal, a contract is a list of type-specific functions that are > needed to implement a generic algorithm. Generally, it will contain default > implementations for these functions, but these are optional. (If default > implementations are not included, an adapter will always be necessary.) The > default implementations are unconstrained generic code; if they compile > successfully with a given set of type parameters, those parameters fulfill > the contract. > > contract Adder(T) { > Zero() T { > return 0 > } > Add(a, b T) T { > return a + b > } > } > > A generic function that uses a contract calls the functions in the > contract to perform operations on generic values: > > func SumSlice(type T Adder)(s []T) T { > sum := Zero() > for _, t := range s { > sum = Add(sum, t) > } > return sum > } > > I see that in the proposal (nice and short) you imply a relationship between the function invocation and the contract. Is it really implicit (it isn't to my sleep-addled brain) that Zero within SumSlice is restricted by contract Adder, simply because its argument is of type "type T Adder"? I would think that invoking Adder.Zero() or even T.Zero() would be necessary or at least more explicit?
In other respects, I doff my hat to you, Andy :-). The rest of your document (the crucial "adaptors") I still need to assimilate. Lucio. -- 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.
