def match?(str, parser=nil)
      node = self.class.parse(str.to_s, parser) rescue (return false)
      self == node
    end
def match?(str, parser=nil)
      node = self.class.parse(str.to_s, parser) rescue (return false)
      self == node
    end
Return true if `str' is parsed to something `==' to this Node.
 str is first converted to a String using #to_s, then given to
 self.class.parse (along with the optional `parser').