def on_slim_attrvalue(escape, code)
      # We perform attribute merging on Array values
      if delimiter = options[:merge_attrs][@attr]
        tmp = unique_name
        [:multi,
         [:code, "#{tmp} = #{code}"],
         [:if, "Array === #{tmp}",
          [:multi,
           [:code, "#{tmp} = #{tmp}.flatten"],
           [:code, "#{tmp}.map!(&:to_s)"],
           [:code, "#{tmp}.reject!(&:empty?)"],
           [:escape, escape, [:dynamic, "#{tmp}.join(#{delimiter.inspect})"]]],
          [:escape, escape, [:dynamic, tmp]]]]
      else
        [:escape, escape, [:dynamic, code]]
      end
    end
def on_slim_attrvalue(escape, code)
      # We perform attribute merging on Array values
      if delimiter = options[:merge_attrs][@attr]
        tmp = unique_name
        [:multi,
         [:code, "#{tmp} = #{code}"],
         [:if, "Array === #{tmp}",
          [:multi,
           [:code, "#{tmp} = #{tmp}.flatten"],
           [:code, "#{tmp}.map!(&:to_s)"],
           [:code, "#{tmp}.reject!(&:empty?)"],
           [:escape, escape, [:dynamic, "#{tmp}.join(#{delimiter.inspect})"]]],
          [:escape, escape, [:dynamic, tmp]]]]
      else
        [:escape, escape, [:dynamic, code]]
      end
    end
Handle attribute expression `[:slim, :attrvalue, escape, code]`

 @param [Boolean] escape Escape html
 @param [String] code Ruby code
 @return [Array] Compiled temple expression