From 10e82de87b48800a7e94c3e89944faca3a7d904f Mon Sep 17 00:00:00 2001
From: Yorick Peterse <yorickpeterse@gmail.com>
Date: Wed, 27 Aug 2014 20:26:10 +0200
Subject: [PATCH] Handle boolean values in predicate results.

---
 lib/oga/xpath/evaluator.rb | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/lib/oga/xpath/evaluator.rb b/lib/oga/xpath/evaluator.rb
index f999a05..fa7e680 100644
--- a/lib/oga/xpath/evaluator.rb
+++ b/lib/oga/xpath/evaluator.rb
@@ -161,8 +161,13 @@ module Oga
             if retval.is_a?(Numeric)
               new_nodes << current if retval.to_i == xpath_index
 
-            # Node sets, strings, etc
-            elsif retval and !retval.empty?
+            # Node sets, strings, booleans, etc
+            elsif retval
+              # Empty strings and node sets evaluate to false.
+              if retval.respond_to?(:empty?) and retval.empty?
+                next
+              end
+
               new_nodes << current
             end
           end