golang 関数のコード生成

package main

import (
    "fmt"
    "text/template"
)

type ErrorInfo struct {
    ID         string
    Description string
}

func main() {
    tpl, err := template.New("error").Parse(`
error {{ .ID }}:
{{- if .Description }}
// Description: {{ .Description }}
{{- end }}
func (e *errStruct) Error() string {
    return {{ printf "error%s" .ID }}
}
`)
    if err != nil {
        panic(err)
    }

    for _, errorInfo := range []ErrorInfo{
        {ID: "InvalidInput", Description: "The input provided was invalid"},
        {ID: "Timeout", Description: "The operation timed out"},
    } {
        errStruct := &errStruct{errorInfo}
        err := tpl.Execute(errStruct, errStruct)
        if err != nil {
            panic(err)
        }
        fmt.Println(errStruct)
    }
}

type errStruct struct {
    ErrorInfo
}

{InvalidInput InvalidInput: The input provided was invalid}
{Timeout Timeout: The operation timed out}