def ruby_aocolumns
      result = []
      column_def_keys = %w[ asSorting bSearchable bSortable
                            bUseRendered bVisible fnRender iDataSort
                            mDataProp sClass sDefaultContent sName
                            sSortDataType sTitle sType sWidth link_to ]
                            index = 0
                            @datatable.columns.each_value do |column_hash|
                              column_result = {}
                              column_hash.each do |key,value|
                                if column_def_keys.include?(key.to_s)
                                  column_result[key.to_s] = value
                                end
                              end

                              # rewrite any link_to values as fnRender functions
                              if column_result.include?('link_to')
                                column_result['fnRender'] = %Q|function(oObj) { return replace('#{column_result['link_to']}', oObj.aData);}|
                                column_result.delete('link_to')
                              end

                              if column_result.empty?
                                result << nil
                              else
                                result << column_result
                              end
                            end
                            result
    end
def ruby_aocolumns
      result = []
      column_def_keys = %w[ asSorting bSearchable bSortable
                            bUseRendered bVisible fnRender iDataSort
                            mDataProp sClass sDefaultContent sName
                            sSortDataType sTitle sType sWidth link_to ]
                            index = 0
                            @datatable.columns.each_value do |column_hash|
                              column_result = {}
                              column_hash.each do |key,value|
                                if column_def_keys.include?(key.to_s)
                                  column_result[key.to_s] = value
                                end
                              end

                              # rewrite any link_to values as fnRender functions
                              if column_result.include?('link_to')
                                column_result['fnRender'] = %Q|function(oObj) { return replace('#{column_result['link_to']}', oObj.aData);}|
                                column_result.delete('link_to')
                              end

                              if column_result.empty?
                                result << nil
                              else
                                result << column_result
                              end
                            end
                            result
    end
returns a ruby hash of