http://play.golang.org/p/O_qWlJo3fT

typeSwitch.go

package main

import (
	"fmt"
	"log"
)

type Value struct {
	Name	string
	Value	interface{}
}

func (v Value) String() string {
	return fmt.Sprintf("<<%s,%v>>", v.Name, v.Value)
}

func main() {
	var I []interface{}

	// Just in a block for readability, no other reason...
	{
		I = append(I, 3)
		I = append(I, Value{Name: "int", Value: 1})
		I = append(I, Value{Name: "int32", Value: 'A'})
		I = append(I, Value{Name: "float64", Value: 1e-1})
		I = append(I, Value{Name: "complex128", Value: (1e-1 + 1e0i)})
	}

	for _, i := range I {
		switch i.(type) {
		case int, int8, int32, int64:
			log.Printf("Type: %T, Value: %v", i, i)
		case float32, float64:
			log.Printf("Type: %T, Value: %v", i, i)
		case complex64, complex128:
			log.Printf("Type: %T, Value: %v", i, i)
		case string:
			log.Printf("Type: %T, Value: %v", i, i)
		case byte:
			log.Printf("Type: %T, Value: %v", i, i)
		case Value:
			if iv, ok := i.(Value); ok {
				switch iv.Value.(type) {
				case int, int8, int32, int64:
					log.Printf("Value.Value:: Type: %T, Value: %v (iv::%v)", iv.Value, iv.Value, iv)
				case float32, float64:
					log.Printf("Value.Value:: Type: %T, Value: %v (iv::%v)", iv.Value, iv.Value, iv)
				case complex64, complex128:
					log.Printf("Value.Value:: Type: %T, Value: %v (iv::%v)", iv.Value, iv.Value, iv)
				default:
					log.Fatalf("Value.Value:: Case not handled (%v::%v)", iv, ok)
				}
			} else {
				log.Fatalf("i.(Value):: Case not handled (%v::%v)", iv, ok)
			}
		default:
			log.Fatal("Case not handled")
		}
	}
	log.Print("Everything went fine!")
}