GoLang: Refactoring xml tag definition in struct

It's not a headache to repeat a tag whenever you need it. Note that the spec does not allow you to use constants or variables when defining tags for struct fields. The struct tag can only be a string literal. Quoting from Spec: Struct types:

StructType    = "struct" "{" { FieldDecl ";" } "}" .
FieldDecl     = (IdentifierList Type | EmbeddedField) [ Tag ] .
EmbeddedField = [ "*" ] TypeName .
Tag           = string_lit .

One way to "outsource" the tag definition would be to "outsource" the whole struct field into another struct, and have Social embed that struct.

For example:

type Social struct {
    XMLName xml.Name `xml:"social"`
    HasFacebook
    Twitter string `xml:"twitter"`
    Youtube string `xml:"youtube"`
}

type HasFacebook struct {
    Facebook string `xml:"facebook"`
}

And now you can reuse it in other types / structs:

type Social2 struct {
    HasFacebook
    Linkedin string `xml:"linkedin"`
}

Testing both types (Social and Social2):

func main() {
    var s *Social
    if err := xml.Unmarshal([]byte(src), &s); err != nil {
        panic(err)
    }
    fmt.Printf("%+v\n", s)

    var s2 *Social2
    if err := xml.Unmarshal([]byte(src), &s2); err != nil {
        panic(err)
    }
    fmt.Printf("%+v\n", s2)
}

const src = `<social>
    <facebook>someface</facebook>
    <twitter>sometwitter</twitter>
    <linkedin>somelinkedin</linkedin>
</social>`

Output (try it on the Go Playground):

&{XMLName:{Space: Local:social} HasFacebook:{Facebook:someface} Twitter:sometwitter Youtube:}
&{HasFacebook:{Facebook:someface} Linkedin:somelinkedin}