firstlast.go
func Last(n int) Filter {
	return FilterFunc(func(arg Arg) error {
		r := newRing(n)
		for s := range arg.In {
			r.pushBack(s)
		}
		for !r.empty() {
			arg.Out <- r.popFront()
		}
		return nil
	})
}
func Last(n int) Filter {
	return FilterFunc(func(arg Arg) error {
		r := newRing(n)
		for s := range arg.In {
			r.pushBack(s)
		}
		for !r.empty() {
			arg.Out <- r.popFront()
		}
		return nil
	})
}
func Last ( n int ) Filter { return FilterFunc ( func ( arg Arg ) error { r := newRing ( n ) for s := range arg . In { r . pushBack ( s ) } for ! r . empty ( ) { arg . Out <- r . popFront ( ) } return nil } ) }
// Last yields the last n items that it receives.
Last yields the last n items that it receives .