From: William James <w_a_x_man@...>
Date: 2006-02-26T05:33:33+09:00
Subject: Re: Xpath to attributes

listrecv@gmail.com wrote:
> Thanks.
>
> But I'd like to just extract the attribute value via Xpath.
>
> If my Xpath is correct, I could just do '//customer/phone/@type' to get
> 'home'.  Is there any way I can do this in Ruby?


p DATA.read.xchain('customer/@loc="south"/phone').first.atr['type']

__END__
<customer loc="north">
  <phone type='home'>0115</phone>
  <phone type='mobi'>07807</phone>
</customer>
<customer loc="south">
  <phone type='home'>0319</phone>
</customer>


The rest:

class Array; alias atr first; alias txt last  end
class String
  def xtag(s)
    result = []
    scan( %r!
              < #{s}  (?: \s+ (  [^>]*  )  )? / >
              |
              < #{s}  (?: \s+ (  [^>]*  )  )? >
              ( .*? )  </ #{s} >
          !mx )  \
      { |unpaired, attr, data|   h = { }
        attr = ( unpaired || attr )
        attr.scan( %r{  ( \S+ ) = ( ["'] ) ( .*? ) \2  }x ){ |k,q,v|
          h[k] = v }   if attr
        block_given? ? ( yield [ h, data ] ) : result << [ h, data ]
      }
    result
  end
  def xchain(s)
    s.scan(%r! [^/"]+ (?: "[^"]*" )? !x).inject([[nil,self]]){|ary,str|
      if "@" == str[0,1]
        str =~ /@(.*?)="(.*)"/
        ary.select{|a,t| a[$1] == $2 }
      else
        return []  if [] == ary
        ary[0].txt.xtag(str)
      end
    }
  end
end