Thanks for the reply. Indeed the solution for what I was trying to do was
to use the interface as the param, not a pointer to the concrete type. I
had initially tried to pass a pointer to an interface which of course did
not work.
On Wednesday, February 8, 2017 at 11:12:54 PM UTC+1, Ron Evans wrote:
>
> I am trying to use an embedded type that implements an interface, in order
> to provide some functional options to a group of related types.
>
> However, I am receiving an error that I cannot use the embedded type to
> call the option function.
>
> Here is a contrived example. A type "Waiter" implements the "TableServer"
> interface using the type "tableserver".
>
> The error is "cannot use SetTable(9) (type func(*tableServer)) as type
> func(*Waiter) in argument to NewWaiter"
>
>
> package main
>
> import "fmt"
>
> type tableServer struct {
> table int
> }
>
> type TableServer interface {
> SetTable(table int)
> GetTable() int
> }
>
> func NewTableServer() TableServer {
> return &tableServer{}
> }
>
> func (i *tableServer) SetTable(table int) {
> i.table = table
> }
>
> func (i *tableServer) GetTable() int {
> return i.table
> }
>
> func SetTable(table int) func(*tableServer) {
> return func(i *tableServer) {
> i.SetTable(table)
> }
> }
>
> type Waiter struct {
> Name string
> TableServer
> }
>
> func NewWaiter(name string, options ...func(*Waiter)) *Waiter {
> w := &Waiter{
> Name: name,
> TableServer: NewTableServer(),
> }
>
> for _, option := range options {
> option(w)
> }
>
> return w
> }
>
> func main() {
> waiter := NewWaiter("joe")
> fmt.Println(waiter.Name, "is working table", waiter.GetTable())
>
> // the following line cannot compile, with error:
> // ./opts.go:56: cannot use SetTable(9) (type func(*tableServer)) as
> type func(*Waiter) in argument to NewWaiter
> waiter = NewWaiter("bob", SetTable(9))
> fmt.Println(waiter.Name, "is working table", waiter.GetTable())
> }
>
>
> Any suggestions? Thanks in advance!
>
>
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