class Terminal::Table

def render_headings
  Y + headings.map_with_index do |heading, i|
    width = 0
    if heading.is_a?(Hash) and !heading[:colspan].nil?
      i.upto(i + heading[:colspan] - 1) do |col|
        width += length_of_column(col)
      end
      width += (heading[:colspan] - 1) * (Y.length + 2)
    else
      width = length_of_column(i)
    end
    Heading.new( width, heading).render
  end.join(Y) + Y
end