Some Guid thing I was playing around with.

guid.go

package guid

import(
    "crypto/rand"
    "encoding/hex"
    "regexp"
    "strconv"
)

type Guid struct{
    Hyphenated bool
    Value      string
}

func (g *Guid) New() string{
    u := make([]byte, 16)
    rand.Read(u)
    u[8] = (u[8] | 0x80) & 0xBF
    u[6] = (u[6] | 0x40) & 0x4F
    raw := hex.EncodeToString(u)
    if g.Hyphenated {
        //ex. 4d23f860-80e6-4984-8e10-5b87ad86c1ff
        tmp := ""
        for i, c := range raw {
            if i == 8 || i == 12 || i == 16 || i == 20{
                tmp += "-"
            }
            l, _ := strconv.Unquote(strconv.QuoteRune(c))
            tmp += l
        }
        g.Value = tmp
    }else{
        g.Value = raw
    }
    return g.Value
}

func (g *Guid) Parse(str string) error {
    if len(str) == 0{
        return errors.New("Invalid arguments for Guid.Parse")
    }
    if !IsGuid(str){
        return errors.New("Invalid Guid format.")
    }
    g.Value = str
    return nil
}

func NewGuid() string{
    g := Guid{}
    return g.New()
}

func NewHyphenatedGuid() string{
    g := Guid{Hyphenated: true}
    return g.New()
}

func IsGuid(str string) (bool, error){
    return regexp.MatchString(
        "^(\\{){0,1}[0-9a-fA-F]{8}\\-[0-9a-fA-F]{4}\\-[0-9a-fA-F]{4}\\-[0-9a-fA-F]{4}\\-[0-9a-fA-F]{12}(\\}){0,1}$", str)
}