hpricot：An Hpricot Showcase：Hpricot Challenge：Putting embedded script in attributes

>> require "hpricot"
=> true
>> a = Hpricot('<a href="http://w.w.w/">Hello</a>')
=> #<Hpricot::Doc {elem <a href="http://w.w.w/"> "Hello" </a>}>
>> (a/"a").first[:href] = "<? echo 'boo' ?>"
=> "<? echo 'boo' ?>"
>> a.to_html
=> "<a href=\"&lt;? echo 'boo' ?&gt;\">Hello</a>"
>> a = Hpricot('<a href="http://w.w.w/">Hello</a>')
=> #<Hpricot::Doc {elem <a href="http://w.w.w/"> "Hello" </a>}>
>>  (a/"a").first.raw_attributes
=> {"href"=>"http://w.w.w/"}
>>  (a/"a").first
=> {elem <a href="http://w.w.w/"> "Hello" </a>}
>>  (a/"a").first.raw_attributes[:href] = "<? echo 'boo' ?>"
=> "<? echo 'boo' ?>"
>> a.to_html
=> "<a href=\"http://w.w.w/\" href=\"<? echo 'boo' ?>\">Hello</a>"

？