func (o option) fullID() string {
	return strings.Join(o.fullIDParts, ".")
}
fullID returns the full ID of the option consisting of all IDs of its parents
joined by dots.
package gonfig
import (
	"encoding"
	"errors"
	"fmt"
	"reflect"
	"strings"
)
const (  
	fieldTagID          = "id"
	fieldTagShort       = "short"
	fieldTagDefault     = "default"
	fieldTagDescription = "desc"
	fieldTagOpts        = "opts"
)
const (  
	fieldOptHidden = "hidden"
)
var (  
	typeOfTextUnmarshaler = reflect.TypeOf((*encoding.TextUnmarshaler)(nil)).Elem()
	typeOfByteSlice       = reflect.TypeOf([]byte{})
)
type option struct {
	value   reflect.Value
	subOpts []*option
	fullIDParts  []string       
	defaultSet   bool           
	defaultValue reflect.Value  
	isParent     bool           
	isMap        bool           
	id     string    
	short  string    
	defaul string    
	desc   string    
	opts   []string  
}