gstring.go
func Printm(format string, args map[string]interface{}) (n int, err error) {
	f, a := gformat(format, args)
	return fmt.Printf(f, a...)
}
func Printm(format string, args map[string]interface{}) (n int, err error) {
	f, a := gformat(format, args)
	return fmt.Printf(f, a...)
}
// Printf prints formatted string to stdout.
// This is same as fmt.Printf, but uses gstring formatting.