Code commenter

Commenter.rb

  class Commenter
    def comment(source)
      output = []
      Open3.popen3(ENV, 'irb', '-f', '--noprompt', '--noverbose') do |stdin, stdout, stderr, wait_thr|
        source.each do |line|
          if empty_line?(line)
            output << line
          else
            stdin.puts line
            output << add_output_to_line(line, stdout.readline)
          end
        end
        stdin.close
      end

      output
    end

    def empty_line?(line)
      line =~ /^\s*($|#)/
    end

    def add_output_to_line(line, output)
      match = line.match(/^[\t ]*([^#"'\r\n]("(\\"|[^"])*"|'(\\'|[^'])*'|[^#\n\r])*)(#\s*=>([^#\r\n]*))?/)

      if match && match[5]
        "#{line[0..match.begin(5)]} => #{output}"
      else
        line
      end
    end
  end