I have argued for a runtime/built-in to do this - it is so common…. (if doing “kind of OO” in Go)
> On Oct 30, 2018, at 7:30 PM, Justin Israel <justinisr...@gmail.com> wrote: > > > > On Wed, Oct 31, 2018 at 11:21 AM <zloikom...@gmail.com > <mailto:zloikom...@gmail.com>> wrote: > Hello, everyone. > Consider following code: > > package main > > import "fmt" > > type implementation struct { > d []int > } > > func (impl *implementation) getData() interface{} { > return impl.d > } > > type phase struct{} > > type data interface { > getData() interface{} > } > > func MakeIntDataPhase() *phase { > return &phase{} > } > > func (p *phase) run(population []data) []data { > return nil > } > > func main() { > var population []implementation > MyPhase := MakeIntDataPhase() > fmt.Println(MyPhase.run(population)) > > } > > When running following code in playground I got following error: > prog.go:30:25: cannot use population (type []implementation) as type []data > in argument to MyPhase.run > If I understand correctly it is because slice of interface type cannot be > converted by the compiler to concrete type. > > What is correct way in golang to implement functionality that is presented in > the example? > When method argument defined using a slice of some interface, how I can pass > it a slice of a concrete type that implements the interface? > > You would end up needing to just do > > func (p *phase) run(population {}interface) []data > > and then type assert the {}interface into []implementation > There isn't a way to directly pass a slice of concrete type to a function > that accepts a slice of interface, unless you first do this: > > iface := make([]data, len(population)) > for i, p := range population { > iface[i] = p > } > MyPhase.run(iface) > > Justin > > -- > 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 > <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.
