gistfile1.txt

package main

import (
	"fmt"
	"reflect"
)

type MyInterface interface {
	Foo() string
}

type TypeA struct {
	ID string
}

func (o *TypeA) Foo() string {
	return o.ID
}

type TypeB struct {
	ID string
}

func findValue(rv reflect.Value) {
	objs := []interface{}{
		&TypeB{"one"},
		&TypeB{"two"},
		&TypeA{"MEEE"},
		&TypeB{"three"},
	}
	//fmt.Printf("%s\n", rv.Elem().Type().Kind())
	//rv := reflect.ValueOf(v)
	for _, obj := range objs {
		robj := reflect.ValueOf(obj)
		if rv.Elem().Type().Kind() == reflect.Struct {
			if robj.Elem().Type().AssignableTo(rv.Elem().Type()) {
				rv.Elem().Set(robj.Elem())
				break
			}
		} else {
			//fmt.Println(rv.Elem().Type())
			if robj.Type().Implements(rv.Elem().Type()) {
				rv.Elem().Set(robj)
				break
			}
		}
	}
}

type T struct {
	F MyInterface
}

func main() {

	var i MyInterface 
	//fmt.Printf("%#v\n", i)
	//fmt.Printf("%#v\n", &i)
	findValue(reflect.ValueOf(&i))
	fmt.Println(i)
	
	var t TypeA
	findValue(reflect.ValueOf(&t))
	fmt.Println(t)
	
	rt := reflect.TypeOf(&T{})
	rf, _ := rt.Elem().FieldByName("F")
	
	v := reflect.New(rf.Type)
	//fmt.Printf("%#v\n", v)
	findValue(v)
	fmt.Println(reflect.Indirect(v).Interface())
	
}