gistfile1.txt

package main

import (
	"bytes"
	"encoding/json"
	"fmt"
)

type Person struct {
	Name string
}

func main() {
	var p Person
	decode(&p)
}

func decode(v interface{}) {
	b := []byte(`{"Name": "joe"}`)
	err := json.NewDecoder(bytes.NewReader(b)).Decode(v)
	if err != nil {
		fmt.Println(err)
		return
	}
	switch t := v.(type) {
	case *Person:
		fmt.Println("saving person", (v).(*Person))
	default:
		err := fmt.Errorf("unknow type %s", t)
		panic(err)
	}
}