insert_grid Sass function

insert_grid.rb

module Sass::Script::Functions
  def insert_grid(columns, width_string)
    assert_type columns, :Number
    assert_type width_string, :String

    width = width_string.match(/\A(\d+)(\w+)\z/)[1]
    type = width_string.match(/\A(\d+)(\w+)\z/)[2]
    raise StandardError, "You must set width_string with unit ie '960px'. " unless ["px","em", "pt", "%"].include?(type)

    grid, grid_segment_width = "", 0
    columns.times do |col|
      grid += "grid_#{col + 1}: {width:#{grid_segment_width += (width.to_i / columns)}#{type}}\n"
    end
    grid += ".column {margin:0,10px;overflow:hidden;float:left;display:inline;}"

    Sass::Script::String.new(grid)
  end
end