gistfile1.rb

class TableDocument
  def to_pdf
    add_text document_title
    add_table [table_header] + table_data
    
    render
  end
  
  def document_title
  
  end
  
  def table_header
    
  end
  
  def table_data
  
  end
end

class ShoppingList < TableDocument
  def document_title
    "Shopping List"
  end
  
  def table_header
    ["Ingredient", "Amount"]
  end
  
  def table_data
    [["Banana", "1"],
     ["Ham", "5"]]
  end
end