dittos.rb

class Cucumber::Ast::Table
  def expand_dittos(ditto = "''")
    ditto_rows = rows.dup

    ditto_rows.each_cons(2) do |upper, lower|
      next unless lower.any? { |cell| cell == ditto }
      lower.each_with_index do |cell, idx|
        lower[idx] = upper[idx] if cell == ditto
      end 
    end

    self.class.new([headers] + ditto_rows)
  end
end