Go语言XML解析中结构体标签的DRY实践

<obj>
    <description>outer object</description>
    <subobjA>
        <description>first kind of subobject</description>
        <foo>some goop</foo>
    </subobjA>
    <subobjB>
        <description>second kind of subobject</description>
        <bar>some other goop</bar>
    </subobjB>
</obj>

package main

import (
    "encoding/xml"
    "fmt"
)

// describable 结构体封装了共同的 Description 字段及其 XML 标签
type describable struct {
    Description string `xml:"description"`
}

// subobjA 嵌入了 describable 结构体
type subobjA struct {
    describable // 匿名嵌入
    XMLName     xml.Name `xml:"subobjA"`
    Foo         string   `xml:"foo"`
}

// subobjB 嵌入了 describable 结构体
type subobjB struct {
    describable // 匿名嵌入
    XMLName     xml.Name `xml:"subobjB"`
    Bar         string   `xml:"bar"`
}

// obj 结构体也嵌入了 describable，并包含 subobjA 和 subobjB
type obj struct {
    describable // 匿名嵌入
    XMLName     xml.Name `xml:"obj"`
    A           subobjA  `xml:"subobjA"`
    B           subobjB  `xml:"subobjB"`
}

func main() {
    sampleXml := `
<obj>
    <description>outer object</description>
    <subobjA>
        <description>first kind of subobject</description>
        <foo>some goop</foo>
    </subobjA>
    <subobjB>
        <description>second kind of subobject</description>
        <bar>some other goop</bar>
    </subobjB>
</obj>`

    var sampleObj obj
    err := xml.Unmarshal([]byte(sampleXml), &sampleObj)
    if err != nil {
        fmt.Printf("XML Unmarshal error: %v\n", err)
        return
    }

    // 访问提升的字段
    fmt.Printf("Outer Description: %s\n", sampleObj.Description)
    fmt.Printf("SubobjA Description: %s\n", sampleObj.A.Description)
    fmt.Printf("SubobjB Description: %s\n", sampleObj.B.Description)
    fmt.Printf("SubobjA Foo: %s\n", sampleObj.A.Foo)
    fmt.Printf("SubobjB Bar: %s\n", sampleObj.B.Bar)
}