1  <%- row_class = cycle("even", "odd") -%>
   2  <%- for item in @items do -%>
   3    <tr class="<%= row_class %>">
   4      ... use item ...
   5    </tr>
   6  <%- end -%>

   1    def cycle(first_value, *values)
   2      values.unshift(first_value)
   3      return Cycle.new(*values)
   4    end
   5  
   6    class Cycle
   7      def initialize(first_value, *values)
   8        @values = values.unshift(first_value)
   9        @index = 0
  10      end
  11  
  12      def to_s
  13        value = @values[@index].to_s
  14        @index = (@index + 1) % @values.size
  15        return value
  16      end
  17    end