Unmarshalling XML into interfaces created at runtime based on the XML.

I'm hoping to be able to do something like this...

/** source xml:
<things>
    <thing type="Point">
        <x>1</x>
        <y>2</y>
    </thing>
</things>
*/

type Thing interface { /* .. */ }

// note: Point would implement Thing
type Point struct {
    X float64 `xml:"x"`
    Y float64 `xml:"y"`
}

type SomeThings struct {
    Things []Thing `xml:"thing"`
}

func UnmarshalThings(xml []byte) (some *SomeThings, err error) {
    some = &SomeThings{}
    err = xml.Unmarhal(xml, someThings)
    return
}

Now, that won't work as-is. When unmarshalled there will be 1 "Thing" with a value of nil. What I'm hoping is that there might be a way for me - even as a post-process step - to get the "type" attribute from <Thing>, call reflect.New to create the Point, and then unmarshal the inner XML into that.

Is something like this doable or is there a library out there someone has written to do this already?

Thanks!

https://play.golang.org/p/06les9YDNg

Thank you very much for this!