Nullable types friendly to json.Encoder, json.Decoder, database/sql, fmt.Stringer, text/template, html/template, some of ORMs.
Supported types:
- NullBool
- NullString
- NullFloat64
- NullInt64
- NullTime
import "github.com/mattn/go-nulltype" type User struct { Namenulltype.NullString `json:"name"` }var user User fmt.Println(user.Name.Valid()) // false fmt.Println(user.Name) // "" user.Name.Set("Bob") fmt.Println(user.Name.Valid()) // true fmt.Println(user.Name) // "Bob" fmt.Println(user.Name.StringValue() == "Bob") // true user.Name.Reset() fmt.Println(user.Name.Valid()) // false fmt.Println(user.Name) // ""var user User fmt.Println(user.Name.Valid()) // false json.NewEncoder(os.Stdout).Encode(user) // {"name": null} user.Name.Set("Bob") fmt.Println(user.Name.Valid()) // true json.NewEncoder(os.Stdout).Encode(user) // {"name": "Bob"}var user User s := `{"name": "Bob"}` json.NewDecoder(strings.NewReader(s)).Decode(&user) fmt.Println(user.Name.Valid()) // true fmt.Println(user.Name) // "Bob" s = `{"name": null}` json.NewDecoder(strings.NewReader(s)).Decode(&user) fmt.Println(user.Name.Valid()) // false fmt.Println(user.Name) // ""var user User db.QueryRow(`SELECT name FROM users`).Scan(&user.Name) fmt.Println(user.Name.Valid()) // true or false fmt.Println(user.Name) // "Bob" or "" db.Exec(`INSERT INTO users(name) VALUES($1)`, user.Name)Struct tag with gorp.
type Post struct { Id int64 `db:"post_id"` Created int64 Title string `db:",size:50"` Body nulltype.NullString `db:"body,size:1024"` }p := Post{ Created: time.Now().UnixNano(), Title: title, Body: nulltype.NullStringOf(body), } err = dbmap.Insert(&p)go get github.com/mattn/go-nulltype MIT
Yasuhiro Matsumoto