Golang泛型-简单用例

Question

Say I have 3 structs:

type A struct{
   Foo map[string]string
}

type B struct{
   Foo map[string]string
}

type C struct{
   Foo map[string]string
}

and then I want to create a function that can accept any of those structs:

func handleFoo (){

}

Is there any way to do this with Golang? Something like:

type ABC = A | B | C

func handleFoo(v ABC){
   x: = v.Foo["barbie"] // this would be nice!
}

OK, so let's try an interface:

type FML interface {
  Bar() string
}

func handleFoo(v FML){
   z := v.Bar() // this will compile
   x: = v.Foo["barbie"] // this won't compile - can't access properties like Foo from v
}

In a language which encourages/forces composition, I cannot understand why you can't access properties like Foo.

Answer 1

Because A, B, and C are are all assignable to the same underlying type, you can use a function with an argument of that underlying type: func handleFoo(v struct{ Foo map[string]string })

Run it on the playground.

A limitation of this approach is that methods on A, B and C (even with the same name and signature), are not available in handleFoo.