# File lib/rake/trace_output.rb, line 9
 9:     def trace_on(out, *strings)
10:       sep = $\ || "\n"
11:       if strings.empty?
12:         output = sep
13:       else
14:         output = strings.map { |s| s.end_with?(sep) ? s : s + sep }.join
15:       end
16:       out.print(output)
17:     end