hpricot：Hpricot::Elements#add_class

everyday Ruby

途中まで、まんま

>> require "hpricot"
=> true
>> doc = Hpricot('<p>foo1</p><p>foo2</p>')
=> #<Hpricot::Doc {elem <p> "foo1" </p>} {elem <p> "foo2" </p>}>
>> (doc/"p").add_class("bacon")
=> #<Hpricot::Elements[{elem <p class="bacon"> "foo1" </p>}, {elem <p class="bacon"> "foo2" </p>}]>
>> doc.to_html
=> "<p class=\"bacon\">foo1</p><p class=\"bacon\">foo2</p>"
>> doc = Hpricot('<p>foo1</p><p>foo2</p>')
=> #<Hpricot::Doc {elem <p> "foo1" </p>} {elem <p> "foo2" </p>}>
>> (doc % "p").add_class("bacon")
NoMethodError: undefined method `add_class' for {elem <p> "foo1" </p>}:Hpricot::Elem
	from (irb):6
>> (doc % "p").get_attribute('class').to_s.split(" ")
=> []
>> (doc % "p").set_attribute('class', "bacon")
=> "bacon"
>> doc.to_html
=> "<p class=\"bacon\">foo1</p><p>foo2</p>"