def on_html_attr(name, value)
      if value[0] == :slim && value[1] == :attrvalue && !options[:merge_attrs][name]
        # We handle the attribute as a boolean attribute
        escape, code = value[2], value[3]
        case code
        when 'true'
          [:html, :attr, name, [:multi]]
        when 'false', 'nil'
          [:multi]
        else
          tmp = unique_name
          [:multi,
           [:code, "#{tmp} = #{code}"],
           [:if, tmp,
            [:if, "#{tmp} == true",
             [:html, :attr, name, [:multi]],
             [:html, :attr, name, [:escape, escape, [:dynamic, tmp]]]]]]
        end
      else
        # Attribute with merging
        @attr = name
        super
      end
    end
def on_html_attr(name, value)
      if value[0] == :slim && value[1] == :attrvalue && !options[:merge_attrs][name]
        # We handle the attribute as a boolean attribute
        escape, code = value[2], value[3]
        case code
        when 'true'
          [:html, :attr, name, [:multi]]
        when 'false', 'nil'
          [:multi]
        else
          tmp = unique_name
          [:multi,
           [:code, "#{tmp} = #{code}"],
           [:if, tmp,
            [:if, "#{tmp} == true",
             [:html, :attr, name, [:multi]],
             [:html, :attr, name, [:escape, escape, [:dynamic, tmp]]]]]]
        end
      else
        # Attribute with merging
        @attr = name
        super
      end
    end
Handle attribute expression `[:html, :attr, name, value]`

 @param [String] name Attribute name
 @param [Array] value Value expression
 @return [Array] Compiled temple expression