I’ve updated my gist at https://gist.github.com/andybalholm/acecba3acf57bf1254142dadce928890 <https://gist.github.com/andybalholm/acecba3acf57bf1254142dadce928890> to use contracts as adaptors.
Andy > On Nov 6, 2018, at 8:27 PM, Andy Balholm <andybalh...@gmail.com> wrote: > > It is implicit: the functions defined in the contract are available (in > scope) in generic functions that use the contract. > > I’m thinking about revising how the adaptors work. I might let contracts act > as adaptors. But I don’t have time to work on it any more today. > > Andy > >> On Nov 5, 2018, at 7:59 PM, Lucio <lucio.d...@gmail.com >> <mailto:lucio.d...@gmail.com>> wrote: >> >> 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 >> <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 >> <mailto:golang-nuts+unsubscr...@googlegroups.com>. >> For more options, visit https://groups.google.com/d/optout >> <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.
