名前付きstring型をScanしたい時（database.sql.Scanner）

package main

import "fmt"

type Animal string

const (
    Cat Animal = "cat"
    Dog Animal = "dog"
)

func (a *Animal) Scan(src interface{}) error {
    str := fmt.Sprintf("%s", src)
    *a = Animal(str)
    return nil
}

func main() {
    var animal Animal
    animal.Scan("cat")
    fmt.Println(animal)

    fmt.Println(animal.Scan("monkey"))
}

run:

cat
<nil>

Playground

よく忘れるので・・・

参考

• http://stackoverflow.com/questions/24264485/saving-enumerated-values-to-a-database