interface item { 
      operator int();                        // returns item index
      
      void configure(char* cmd);    // calls canvas::itemconfigure
      
      void tag(char* s);                      // sets tag for item
      char* tags();              // delivers tags set for the item
      void move(int x, int y);
      
      bind(char *b, handler* h, char* args = "" );
      bind(char *b, binding* ac, char* args = "" );
      
      handler(class handler* h, char* args = "" );
      handler(binding* ac, char* args = "" );
      
    protected:
      virtual install(action&,char* args="");    // default bindings
    };