ds={
	"init":func(end){@end=end; @current=0; @prev=@current},
	"current":func(){prev},
	"next":func(){
		(current <= end) ? [true] {@current=current+1; @prev=current} :: {nil}
	},
	"reset":func(){@current=0; @prev=@current}
}

// Example
//;
//it=$(ds,3);
//it++;
//it."reset"
//it++;
//it++;
//add(it)

