与上下文无关的XML结构标记

Question

I would like to be able to tag my struct without it needing to know what level it will be nested into an XML document. In other words, I want to be able to write:

type Elem struct {
    Datum string `xml:"datum"`
}

And have it work for both

<elem>
    <datum>Hello</datum>
</elem>

And

<list>
    <elem>
        <datum>Hello</datum>
    </elem>
</list>

However, in order for the latter example to work (when attempting to decode into a []Elem), I need to use the tag xml:"elem>datum", which decodes incorrectly for the first example. Is there a way for me to define an XML tag without knowing how the struct will be embedded? See here for a simple example:

http://play.golang.org/p/LpI2vKFpNE

Answer 1

One way to solve this is through the use of an anonymous struct:

func Test2_DecodeList() {
    xmlData := "<list><elem><datum>Hello</datum></elem></list>"
    var list struct {
        Elems []Elem `xml:"elem"`
    }
    if err := xml.Unmarshal([]byte(xmlData), &list); err != nil {
        fatal("Test2:", err)
    }

    if err := expectEq(1, len(list.Elems)); err != nil {
        fatal("Test2:", err)
    }

    if err := expectEq("Hello", list.Elems[0].Datum); err != nil {
        fatal("Test2:", err)
    }
}

Example: http://play.golang.org/p/UyYoyGgL_K