}

// drain returns a single string representing the processed input tokens.
func drain(input *Input) string {
	var buf strings.Builder
	for {
		tok := input.Next()
		if tok == scanner.EOF {
			return buf.String()
		}
		if tok == '#' {
			continue
		}
		if buf.Len() > 0 {
			buf.WriteByte('.')
		}
		buf.WriteString(input.Text())
	}
}

type badLexTest struct {