--- a/src/YAMLCommand.h	Sat Dec 05 19:32:05 2020 +0100
+++ b/src/YAMLCommand.h	Sat Dec 05 19:42:21 2020 +0100
@@ -32,6 +32,9 @@
 
 class YAMLCommand {
 private:
+	using string_t = relpipe::writer::string_t;
+	using RelpipeWriterException = relpipe::writer::RelpipeWriterException;
+
 	std::wstring_convert<codecvt_utf8<wchar_t>> convertor; // YAML strings are in UTF-8
 
 	class YAMLEvent {
@@ -50,12 +53,12 @@
 			return event.type;
 		}
 
-		const relpipe::writer::string_t getTypeName() const {
+		const string_t getTypeName() const {
 			return findTypeName(event.type);
 		}
 
 		/** Just for debugging and error handling */
-		static const relpipe::writer::string_t findTypeName(const yaml_event_type_t eventType) {
+		static const string_t findTypeName(const yaml_event_type_t eventType) {
 			if (eventType == YAML_NO_EVENT) return L"NO";
 			else if (eventType == YAML_STREAM_START_EVENT) return L"STREAM_START";
 			else if (eventType == YAML_STREAM_END_EVENT) return L"STREAM_END";
@@ -119,30 +122,30 @@
 	YAMLParser parser;
 	std::shared_ptr<relpipe::writer::RelationalWriter> writer;
 
-	relpipe::writer::string_t relationName;
-	std::vector<relpipe::writer::string_t> record;
+	string_t relationName;
+	std::vector<string_t> record;
 	std::vector<relpipe::writer::AttributeMetadata> attributesMetadata;
 
-	relpipe::writer::string_t y2s(const yaml_char_t* value) {
+	string_t y2s(const yaml_char_t* value) {
 		return value ? convertor.from_bytes((const char*) value) : L"";
 	}
 
-	relpipe::writer::string_t fetchScalarValue(YAMLEvent_p event) {
+	string_t fetchScalarValue(YAMLEvent_p event) {
 		if (event->getType() == YAML_SCALAR_EVENT) return y2s(event->getEvent()->data.scalar.value);
-		else throw relpipe::writer::RelpipeWriterException(L"Invalid YAML structure: expected SCALAR but got: " + event->getTypeName());
+		else throw RelpipeWriterException(L"Invalid YAML structure: expected SCALAR but got: " + event->getTypeName());
 	}
 
-	void consumeEvent(const yaml_event_type_t expectedEventType, relpipe::writer::string_t expectedScalarValue = L"") {
+	void consumeEvent(const yaml_event_type_t expectedEventType, string_t expectedScalarValue = L"") {
 		YAMLEvent_p event = YAMLEvent_p(parser.next());
-		if (!event) throw relpipe::writer::RelpipeWriterException(L"Invalid YAML structure: missing event: " + YAMLEvent::findTypeName(expectedEventType));
-		if (event->getType() != expectedEventType) throw relpipe::writer::RelpipeWriterException(L"Invalid YAML structure: expected event: " + YAMLEvent::findTypeName(expectedEventType) + L", but got: " + event->getTypeName());
-		if (expectedEventType == YAML_SCALAR_EVENT && expectedScalarValue.size() && expectedScalarValue != fetchScalarValue(event)) throw relpipe::writer::RelpipeWriterException(L"Invalid YAML structure: expected scalar value: " + expectedScalarValue + L", but got " + fetchScalarValue(event));
+		if (!event) throw RelpipeWriterException(L"Invalid YAML structure: missing event: " + YAMLEvent::findTypeName(expectedEventType));
+		if (event->getType() != expectedEventType) throw RelpipeWriterException(L"Invalid YAML structure: expected event: " + YAMLEvent::findTypeName(expectedEventType) + L", but got: " + event->getTypeName());
+		if (expectedEventType == YAML_SCALAR_EVENT && expectedScalarValue.size() && expectedScalarValue != fetchScalarValue(event)) throw RelpipeWriterException(L"Invalid YAML structure: expected scalar value: " + expectedScalarValue + L", but got " + fetchScalarValue(event));
 	}
 
-	relpipe::writer::string_t consumeScalarEvent() {
+	string_t consumeScalarEvent() {
 		YAMLEvent_p event = YAMLEvent_p(parser.next());
 		if (event && event->getType() == YAML_SCALAR_EVENT) return fetchScalarValue(event);
-		else throw relpipe::writer::RelpipeWriterException(L"Invalid YAML structure: expected SCALAR, but got: " + event->getTypeName());
+		else throw RelpipeWriterException(L"Invalid YAML structure: expected SCALAR, but got: " + event->getTypeName());
 	}
 
 	bool until(const yaml_event_type_t until, YAMLEvent_p& event) {
@@ -154,7 +157,7 @@
 		YAMLEvent_p event = YAMLEvent_p(parser.next());
 		if (event->getType() == YAML_MAPPING_START_EVENT) processRelationWithMetadata();
 		else if (event->getType() == YAML_SEQUENCE_START_EVENT)processRelationWithoutMetadata();
-		else throw relpipe::writer::RelpipeWriterException(L"Invalid YAML structure: expected MAPPING or SEQUENCE, but got: " + event->getTypeName());
+		else throw RelpipeWriterException(L"Invalid YAML structure: expected MAPPING or SEQUENCE, but got: " + event->getTypeName());
 	}
 
 	void processRelationWithMetadata() {
@@ -162,9 +165,9 @@
 		consumeEvent(YAML_SEQUENCE_START_EVENT);
 
 		for (YAMLEvent_p event; until(YAML_SEQUENCE_END_EVENT, event);) {
-			if (event->getType() != YAML_MAPPING_START_EVENT) throw relpipe::writer::RelpipeWriterException(L"Invalid YAML structure: expected MAPPING (attribute-metadata), but got: " + event->getTypeName());
-			relpipe::writer::string_t name;
-			relpipe::writer::string_t type = L"string";
+			if (event->getType() != YAML_MAPPING_START_EVENT) throw RelpipeWriterException(L"Invalid YAML structure: expected MAPPING (attribute-metadata), but got: " + event->getTypeName());
+			string_t name;
+			string_t type = L"string";
 			for (YAMLEvent_p event; until(YAML_MAPPING_END_EVENT, event);) {
 				auto key = fetchScalarValue(event);
 				auto value = consumeScalarEvent();
@@ -185,7 +188,7 @@
 		} else if (event->getType() == YAML_MAPPING_END_EVENT) {
 			// empty relation, no records
 		} else {
-			relpipe::writer::RelpipeWriterException(L"Invalid YAML structure: expected 'record' or MAPPING_END, but got: " + event->getTypeName());
+			RelpipeWriterException(L"Invalid YAML structure: expected 'record' or MAPPING_END, but got: " + event->getTypeName());
 		}
 	}
 
@@ -208,7 +211,7 @@
 
 	void processRecords() {
 		for (YAMLEvent_p event; until(YAML_SEQUENCE_END_EVENT, event);) {
-			if (event->getType() != YAML_MAPPING_START_EVENT) throw relpipe::writer::RelpipeWriterException(L"Invalid YAML structure: expected MAPPING (record), but got: " + event->getTypeName());
+			if (event->getType() != YAML_MAPPING_START_EVENT) throw RelpipeWriterException(L"Invalid YAML structure: expected MAPPING (record), but got: " + event->getTypeName());
 			record.clear();
 			record.resize(attributesMetadata.size());
 			for (YAMLEvent_p event; until(YAML_MAPPING_END_EVENT, event);) {