golangでjsonとyamlを変換

https://qiita.com/daichirata/items/5d751a8a4544434c27b0
これを見て衝撃を受けて、書かずにはいられなかった。

yamlのアンカーとエイリアスには対応してないらしい。

yj.go

package main

import (
    "flag"
    "fmt"
    "io/ioutil"
    "os"

    "encoding/json"
    "github.com/ghodss/yaml"
    yaml2 "gopkg.in/yaml.v2"
)

func main() {
    var (
        jsonFlag bool
        yamlFlag bool
    )
    flag.BoolVar(&jsonFlag, "json", false, "bool flag")
    flag.BoolVar(&yamlFlag, "yaml", false, "bool flag")
    flag.Parse()

    buf, err := ioutil.ReadAll(os.Stdin)
    if err != nil {
        panic(err)
    }

    m := make(map[string]interface{})
    err = yaml.Unmarshal(buf, &m)
    if err != nil {
        panic(err)
    }

    if yamlFlag {
        d, err := yaml2.Marshal(&m)
        if err != nil {
            panic(err)
        }
        fmt.Printf("%s", d)
    }

    if jsonFlag {
        d, err := json.Marshal(&m)
        if err != nil {
            panic(err)
        }
        fmt.Printf("%s", d)
    }
}

ビルドと実行

go build yj.go

cat <<EOD | ./yj -yaml | ./yj -json
{
    "glossary": {
        "title": "example glossary",
        "GlossDiv": {
            "title": "S",
            "GlossList": {
                "GlossEntry": {
                    "ID": "SGML",
                    "SortAs": "SGML",
                    "GlossTerm": "Standard Generalized Markup Language",
                    "Acronym": "SGML",
                    "Abbrev": "ISO 8879:1986",
                    "GlossDef": {
                        "para": "A meta-markup language, used to create markup languages such as DocBook.",
                        "GlossSeeAlso": ["GML", "XML"]
                    },
                    "GlossSee": "markup"
                }
            }
        }
    }
}
EOD

echo 

cat <<EOD | ./yj -json | ./yj -yaml
---
glossary:
  title: example glossary
  GlossDiv:
    title: S
    GlossList:
      GlossEntry:
        ID: SGML
        SortAs: SGML
        GlossTerm: Standard Generalized Markup Language
        Acronym: SGML
        Abbrev: ISO 8879:1986
        GlossDef:
          para: A meta-markup language, used to create markup languages such as DocBook.
          GlossSeeAlso:
          - GML
          - XML
        GlossSee: markup
EOD