filters.go
func Uniq() Filter {
	return FilterFunc(func(arg Arg) error {
		first := true
		last := ""
		for s := range arg.In {
			if first || last != s {
				arg.Out <- s
			}
			last = s
			first = false
		}
		return nil
	})
}
func Uniq() Filter {
	return FilterFunc(func(arg Arg) error {
		first := true
		last := ""
		for s := range arg.In {
			if first || last != s {
				arg.Out <- s
			}
			last = s
			first = false
		}
		return nil
	})
}
// Uniq squashes adjacent identical items in arg.In into a single output.