Methods: package main import "log"; type string_list struct { items []string; } func (self *string_list) Join(sep string)(string) { retval := ""; for i := 0; i < len(self.items); i++ { if i > 0 { retval += sep; } retval += self.items[i]; } return retval; } func main() { log.Stdout((string_list{ items: []string { "え", "っ", "ち" } }).Join("-")); } Interfaces: package main import ( "log"; "strconv"; )