Cope with parsing NLSML documents with no namespaces

Many ASR vendors think this is acceptable. I'm too tired to educate them.

lib/ruby_speech/nlsml/document.rb

@@ -34,13 +34,15 @@ def ==(other)
 
       def input_hash_for_interpretation(interpretation)
         input_element = interpretation.at_xpath 'ns:input', 'ns' => NLSML_NAMESPACE
+        input_element ||= interpretation.at_xpath 'input'
         { content: input_element.content }.tap do |h|
           h[:mode] = input_element['mode'].to_sym if input_element['mode']
         end
       end
 
       def instance_hash_for_interpretation(interpretation)
         instance_element = interpretation.at_xpath 'xf:instance', 'xf' => XFORMS_NAMESPACE
+        instance_element ||= interpretation.at_xpath 'instance'
         return unless instance_element
         element_children_key_value instance_element
       end
@@ -76,7 +78,9 @@ def result
       end
 
       def interpretation_nodes
-        result.xpath('ns:interpretation', 'ns' => NLSML_NAMESPACE).sort_by { |int| -int[:confidence].to_i }
+        nodes = result.xpath 'ns:interpretation', 'ns' => NLSML_NAMESPACE
+        nodes += result.xpath 'interpretation'
+        nodes.sort_by { |int| -int[:confidence].to_i }
       end
     end
   end

spec/ruby_speech/nlsml_spec.rb

@@ -201,5 +201,43 @@
       its(:interpretations)     { should == expected_interpretations }
       its(:best_interpretation) { should == expected_best_interpretation }
     end
+
+    context "with no namespaces (because some vendors think this is ok" do
+      let :example_document do
+        '''
+<result grammar="http://flight">
+  <interpretation confidence="60">
+    <input mode="speech">I want to go to Pittsburgh</input>
+    <model>
+      <group name="airline">
+        <string name="to_city"/>
+      </group>
+    </model>
+    <instance>
+      <airline>
+        <to_city>Pittsburgh</to_city>
+      </airline>
+    </instance>
+  </interpretation>
+  <interpretation confidence="40">
+    <input>I want to go to Stockholm</input>
+    <model>
+      <group name="airline">
+        <string name="to_city"/>
+      </group>
+    </model>
+    <instance>
+      <airline>
+        <to_city>Stockholm</to_city>
+      </airline>
+    </instance>
+  </interpretation>
+</result>
+        '''
+      end
+
+      its(:interpretations)     { should == expected_interpretations }
+      its(:best_interpretation) { should == expected_best_interpretation }
+    end
   end
 end