evaluate_predicate

# File lib/rexml/xpath_parser.rb, line 581
    def evaluate_predicate(expression, nodesets)
      # enter(:predicate, expression, nodesets)
      new_nodesets = nodesets.collect do |nodeset|
        new_nodeset = []
        subcontext = { :size => nodeset.size }
        nodeset.each_with_index do |node, index|
          if node.is_a?(XPathNode)
            subcontext[:node] = node.raw_node
            subcontext[:index] = node.position
          else
            subcontext[:node] = node
            subcontext[:index] = index + 1
          end
          result = expr(expression.dclone, [node], subcontext)
          # trace(:predicate_evaluate, expression, node, subcontext, result)
          result = result[0] if result.kind_of? Array and result.length == 1
          if result.kind_of? Numeric
            if result == node.position
              new_nodeset << XPathNode.new(node, position: new_nodeset.size + 1)
            end
          elsif result.instance_of? Array
            if result.size > 0 and result.inject(false) {|k,s| s or k}
              if result.size > 0
                new_nodeset << XPathNode.new(node, position: new_nodeset.size + 1)
              end
            end
          else
            if result
              new_nodeset << XPathNode.new(node, position: new_nodeset.size + 1)
            end
          end
        end
        new_nodeset
      end
      new_nodesets
    # ensure
    #   leave(:predicate, new_nodesets)
    end