Unmarshaling numbered XML tags in Go

php editor Banana introduces you to the method of unmarshalling numbered XML tags in Go language. The Go language provides the xml.Unmarshal function, which can unmarshal XML data into a Go structure. When unmarshalling, we can use tags to specify the mapping relationship between XML elements and structure fields. By adding `xml:"tagname"` to the tag of the structure field, we can associate specific tags in XML with the structure field to achieve automatic unmarshalling operations. This method is simple and efficient, making processing XML data in Go language easy and enjoyable.

Question content

I've tried a lot of structures to try and unmarshal this xml, but I can't really figure it out:

package main

import (
    "bytes"
    "encoding/xml"
    "fmt"
)

type SettingContainer struct {
    XMLName  xml.Name  `xml:"Settings"`
    Settings []Setting `xml:",any"`
}

type Setting struct {
    XMLName          xml.Name          `xml:",any"`
    SettingRegisters []SettingRegister `xml:",any"`
}

type SettingRegister struct {
    XMLName xml.Name `xml:",any"`
    Value   string   `xml:"value,attr"`
}

func main() {
    var xmlData = bytes.NewBufferString(`
    <Settings>
        <Setting0>
            <Setting0_register value="0x20" />
            <Setting0ArbitraryName value="0x0" />
        </Setting0>
        <Setting1>
            <Setting1_register value="0x60" />
            <Setting1WhateverEnable value="0x0" />
        </Setting1>
        <Setting2>
            <Setting2_register value="0x80" />
            <Setting2blahblah value="0x1" />
        </Setting2>
        <Setting4>
            <Setting4_register value="0x2fffff8" />
            <Setting4ThisCanBeAnything value="0x0" />
        </Setting4>
    </Settings>`)

    var s []SettingContainer
    xml.Unmarshal(xmlData.Bytes(), &s)

    for _, i := range s {
        fmt.Println(i)
    }
}

I just can't get it to print anything. The fields I actually need are the value attr of settingn_register and the settingn tag name. How can I correctly unmarshal the xml into these fields? I'm thinking of making a custom unmarshalling function, but I can't really find how to make one properly. I only get the "settings" tag name from this xml.

Workaround

Remove the xml:",any" tag from the xmlname field (this will cause the decoder to try to add extra child elements mapped to this field) and unmarshal it to settingcontainer instead of []settingcontainer as an xml document can only have one root element. Working example here: https://www.php.cn/link/d2949eb6aaa490c835219e945ff37dad

type SettingContainer struct {
    XMLName  xml.Name  `xml:"Settings"`
    Settings []Setting `xml:",any"`
}

type Setting struct {
    XMLName          xml.Name
    SettingRegisters []SettingRegister `xml:",any"`
}

type SettingRegister struct {
    XMLName xml.Name
    Value   string `xml:"value,attr"`
}

func main() {
    var xmlData = bytes.NewBufferString(`...`)

    var s SettingContainer
    xml.Unmarshal(xmlData.Bytes(), &s)

    fmt.Println(s)
}

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