Go: reflection based generation (https://play.golang.org/p/y5qKxuoV9t)

main.go

package main

import (
	"fmt"
	"reflect"
	"time"
)

type Status struct {
	APC       string
	Date      time.Time
	Hostname  string `key:"HOSTNAME"`
	Version   string `key:"VERSION"`
	UPSName   string `key:"UPS"`
	Cable     string `key:"CABLE"`
	Driver    string `key:"DRIVER"`
	UPSMode   string `key:"UPS"`
	StartTime time.Time
	Model     string
	Status    string
	// ...
}

func Generate(v interface{}) {
	t := reflect.TypeOf(v)
	fmt.Println("func (s *" + t.Name() + ") Set(key string, value string) {")
	defer fmt.Println("}")

	fmt.Println("\tswitch key {")
	defer fmt.Println("\t}")

	for i := 0; i < t.NumField(); i++ {
		f := t.Field(i)
		key := f.Tag.Get("key")
		if key == "" {
			continue
		}

		fmt.Printf("\tcase %q:\n", key)
		fmt.Println("\t\ts." + f.Name + " = value")
	}
}

func main() {
	Generate(Status{})
}