package main

import (
    "encoding/gob"
    "os"
)

type User struct {
    Username string
    Password string
}

func main() {

    user := User{
        "zola",
        "supersecretpassword",
    }

    file, _ := os.Create("user.gob")

    defer file.Close()

    encoder := gob.NewEncoder(file)

    encoder.Encode(user)

}

package main

import (
    "encoding/gob"
    "fmt"
    "os"
)

type User struct {
    Username string
    Password string
}

func main() {

    user := User{}

    file, _ := os.Open("user.gob")

    defer file.Close()

    decoder := gob.NewDecoder(file)

    decoder.Decode(&user)

    fmt.Println(user)

}

package main

import (
    "encoding/gob"
    "fmt"
    "os"
)

type User struct {
    Username string
    Password string
}

type Admin struct {
    Username string
    Password string
    IsAdmin  bool
}

type Deleter interface {
    Delete()
}

func (u User) Delete() {
    fmt.Println("User ==> Delete()")
}

func (a Admin) Delete() {
    fmt.Println("Admin ==> Delete()")
}

func main() {

    user := User{
        "zola",
        "supersecretpassword",
    }

    admin := Admin{
        "john",
        "supersecretpassword",
        true,
    }

    file, _ := os.Create("user.gob")

    adminFile, _ := os.Create("admin.gob")

    defer file.Close()

    defer adminFile.Close()

    gob.Register(User{}) // registering the type allows us to encode it

    gob.Register(Admin{}) // registering the type allows us to encode it

    encoder := gob.NewEncoder(file)

    adminEncoder := gob.NewEncoder(adminFile)

    InterfaceEncode(encoder, user)

    InterfaceEncode(adminEncoder, admin)

}

func InterfaceEncode(encoder *gob.Encoder, d Deleter) {

    if err := encoder.Encode(&d); err != nil {
        fmt.Println(err)
    }

}

package main

import (
    "encoding/gob"
    "fmt"
    "log"
    "os"
)

type User struct {
    Username string
    Password string
}

type Admin struct {
    Username string
    Password string
    IsAdmin  bool
}

type Deleter interface {
    Delete()
}

func (u User) Delete() {
    fmt.Println("User ==> Delete()")
}

func (a Admin) Delete() {
    fmt.Println("Admin ==> Delete()")
}

func main() {

    file, _ := os.Open("user.gob")

    adminFile, _ := os.Open("admin.gob")

    defer file.Close()

    defer adminFile.Close()

    gob.Register(User{}) // registering the type allows us to encode it

    gob.Register(Admin{}) // registering the type allows us to encode it

    var admin Deleter

    var user Deleter

    userDecoder := gob.NewDecoder(file)

    adminDecoder := gob.NewDecoder(adminFile)

    user = InterfaceDecode(userDecoder)

    admin = InterfaceDecode(adminDecoder)

    fmt.Println(user)

    fmt.Println(admin)

}

func InterfaceDecode(decoder *gob.Decoder) Deleter {

    var d Deleter

    if err := decoder.Decode(&d); err != nil {
        log.Fatal(err)
    }

    return d

}