class RuboCop::Cop::Style::BlockComments

def autocorrect(comment)
  expr = comment.loc.expression
  eq_begin = expr.resize("=begin\n".length)
  eq_end = Parser::Source::Range.new(expr.source_buffer,
                                     expr.end_pos - "\n=end".length,
                                     expr.end_pos)
  contents = Parser::Source::Range.new(expr.source_buffer,
                                       eq_begin.end_pos,
                                       eq_end.begin_pos)
  @corrections << lambda do |corrector|
    corrector.remove(eq_begin)
    unless contents.length == 0
      corrector.replace(contents,
                        contents.source
                          .gsub(/\A/, '# ')
                          .gsub(/\n\n/, "\n#\n")
                          .gsub(/\n(?=[^\z#])/, "\n# "))
    end
    corrector.remove(eq_end)
  end
end

def investigate(processed_source)
  processed_source.comments.each do |comment|
    add_offense(comment, :expression) if comment.document?
  end
end