Merge pull request #93 from teamcapybara/custom_attribute

support querying HTML5 attributes with "special" characters in them

lib/xpath/renderer.rb

@@ -59,7 +59,11 @@ def where(on, condition)
     end
 
     def attribute(current, name)
-      "#{current}/@#{name}"
+      if valid_xml_name?(name)
+        "#{current}/@#{name}"
+      else
+        "#{current}/attribute::*[local-name(.) = #{string_literal(name)}]"
+      end
     end
 
     def binary_operator(name, left, right)
@@ -112,5 +116,9 @@ def with_element_conditions(expression, element_names)
         "#{expression}*"
       end
     end
+
+    def valid_xml_name?(name)
+      name =~ /^[a-zA-Z_:][a-zA-Z0-9_:\.\-]*$/
+    end
   end
 end