func (p *ParsingMap) ToCommaList(field string, dest interface{}) *ParsingMap {
	*p = append(*p, ParsingMapElem{Field: field, Fct: ToCommaList, Dest: dest})
	return p
}
ToCommaList is a helper for ToCommaList.
package httpreq
import (
	"errors"
	"strconv"
	"strings"
	"time"
)
var (
	ErrWrongType = errors.New("wrong type for the given convertion function")
)
type ParsingMapElem struct {
	Field string
	Fct   func(string, interface{}) error
	Dest  interface{}
}
type ParsingMap []ParsingMapElem
type Getter interface {
	Get(string) string
}
func NewParsingMap() *ParsingMap {
	return &ParsingMap{}
}
func NewParsingMapPre(n int) *ParsingMap {
	p := make(ParsingMap, 0, n)
	return &p
}
func (p *ParsingMap) Add(field string, fct func(string, interface{}) error, dest interface{}) *ParsingMap {
	*p = append(*p, ParsingMapElem{Field: field, Fct: fct, Dest: dest})
	return p
}
func (p ParsingMap) Parse(in Getter) error {
	for _, elem := range p {
		if e := in.Get(elem.Field); e != "" {
			if err := elem.Fct(e, elem.Dest); err != nil {
				return err
			}
		}
	}
	return nil
}
func ToCommaList(src string, dest interface{}) error {
	d, ok := dest.(*[]string)
	if !ok {
		return ErrWrongType
	}
	*d = strings.Split(src, ",")
	return nil
}