func keys() []string {
	var r []string
	err := db.DB.View(func(tx *bolt.Tx) error {
		var err error
		r, err = db.KeyStrings(tx, "sugtag")
		return err
	})
	if err != nil {
		log.Print(err)
		return nil
	}
	return r
}
keys return datfile names of Sugtaglist.
package suggest
import (
	"log"
	"github.com/boltdb/bolt"
	"github.com/shingetsu-gou/shingetsu-gou/cfg"
	"github.com/shingetsu-gou/shingetsu-gou/db"
	"github.com/shingetsu-gou/shingetsu-gou/record"
	"github.com/shingetsu-gou/shingetsu-gou/tag"
	"github.com/shingetsu-gou/shingetsu-gou/util"
)
func Get(datfile string, def tag.Slice) tag.Slice {
	var r []string
	err := db.DB.View(func(tx *bolt.Tx) error {
		var err error
		r, err = db.MapKeys(tx, "sugtag", []byte(datfile))
		return err
	})
	if err != nil {
		log.Print(err, datfile)
		return def
	}
	tags := make([]*tag.Tag, len(r))
	for i, rr := range r {
		tags[i] = &tag.Tag{
			Tagstr: rr,
		}
	}
	if len(tags) > cfg.TagSize {
		tags = tags[:cfg.TagSize]
	}
	return tag.Slice(tags)
}