Golang: Passing structs as parameters of a function - go

Question

Trying to teach myself some Go by following an online course. And I'm trying to go a bit off course to expand on my learning a bit.
The course had us writing a simple function using a couple variables and the function would take the two variables and print out a line. So I had:
func main() {
var greeting := "hello"
var name := "cleveland"
message := printMessage(greeting,name)
fmt.Println(message)
}
func printMessage(greeting string, name string) (message string) {
return greeting + " " + name + "!"
}
Later the course introduced a way to create an pseudo-array of strings using the using the
func sayHello (cities ...string) (message string) {
for _, city := range cities {
message := printMessage("hello", city)
fmt.Println(message)
}
}
I would like to create a struct with different greetings and pass those into the sayHello function. So the struct and the variables would looks something like this:
type cityInfo struct {
greeting string
name string
wins float32
gamesPlayed float32
}
city1 := cityInfo{"hello", "cleveland"}
city2 := cityInfo{"good morning", "atlanta"}
...and so on
How do I format the function to pass those structs into the function so that I can iterate on the number of structs and get the greetings and names using city.greeting and city.name? Does this question make sense?

Answer 1

Function argument type can be any valid type:
func sayHello (cities ...cityInfo) {
for _, city := range cities {
message := printMessage(city.greeting, city.name)
fmt.Println(message)
}
}

Answer 2

One solution would be to create an interface and a greeting method.
For example:
type Greetable interface {
Greeting() string
Name() string
}
You would then implement the Greeting and Name methods in your struct (this would immediately implement the Greetable interface, due to the way that Go handles interfaces):
type cityInfo struct {
name string
greeting string
}
func (city *cityInfo) Greeting() string {
return city.greeting
}
func (city *cityInfo) Name() string {
return city.name
}
And then your function would just accept anything that implements Greetable:
func sayHello(greetables ...Greetable) (message string)
And use the Name() and Greeting() methods instead.