diff -r 52f837fbb216 -r 018e2609f5bb streamlet-examples/xpath.cpp
--- a/streamlet-examples/xpath.cpp	Tue Jan 28 23:35:25 2020 +0100
+++ b/streamlet-examples/xpath.cpp	Wed Jan 29 00:58:37 2020 +0100
@@ -62,13 +62,6 @@
 		else return STRING;
 	}
 
-	// TODO: should not be done in particular streamlets but in the worker
-	std::wstring toNullValue(std::wstring type) {
-		if (type == BOOLEAN) return L"false";
-		else if (type == INTEGER) return L"0";
-		else return L"";
-	}
-
 	class XPathAttribute {
 	public:
 
@@ -118,30 +111,22 @@
 					result = root->eval_to_boolean(xpath, ns) ? L"true" : L"false";
 				} else if (xpathAttribute.mode == Mode::LINE_NUMBER) {
 					xmlpp::NodeSet attributeNodes = root->find(xpath, ns);
-					if (attributeNodes.size()) {
-						result = std::to_wstring(attributeNodes[0]->get_line());
-					} else {
-						result = L"0";
-						isNull = true;
-					}
+					if (attributeNodes.size()) result = std::to_wstring(attributeNodes[0]->get_line());
+					else isNull = true;
 				} else if (xpathAttribute.mode == Mode::XPATH) {
 					xmlpp::NodeSet attributeNodes = root->find(xpath, ns);
-					if (attributeNodes.size()) {
-						result = convertor.from_bytes(attributeNodes[0]->get_path());
-					} else {
-						result = L"";
-						isNull = true;
-					}
+					if (attributeNodes.size()) result = convertor.from_bytes(attributeNodes[0]->get_path());
+					else isNull = true;
 				} else if (xpathAttribute.mode == Mode::RAW_XML) {
 					throw std::logic_error("Raw XML mode is not yet implemented."); // TODO: implement also RAW_XML
 				} else {
 					throw std::logic_error("Unsupported mode."); // should never happer
 				}
 
-				oa.push_back({result, false});
+				oa.push_back({result, isNull});
 			}
 		} catch (xmlpp::parse_error& e) {
-			for (XPathAttribute xpathAttribute : xpathAttributes) oa.push_back({toNullValue(toType(xpathAttribute.mode)), true});
+			for (XPathAttribute xpathAttribute : xpathAttributes) oa.push_back({L"", true});
 			// invalid XML → xmlpp::parse_error → just skip this file
 			// invalid XPath → xmlpp::exception → failure
 		}