diff -r 000000000000 -r 17fc678e0a94 src/X11Handler.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/X11Handler.h	Sun Mar 28 18:41:21 2021 +0200
@@ -0,0 +1,93 @@
+/**
+ * Relational pipes
+ * Copyright © 2021 František Kučera (Frantovo.cz, GlobalCode.info)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+
+#include <memory>
+#include <string>
+#include <vector>
+#include <iostream>
+#include <sstream>
+#include <locale>
+#include <codecvt>
+#include <stdexcept>
+
+#include <relpipe/reader/typedefs.h>
+#include <relpipe/reader/TypeId.h>
+#include <relpipe/reader/handlers/RelationalReaderStringHandler.h>
+#include <relpipe/reader/handlers/AttributeMetadata.h>
+
+#include "Configuration.h"
+
+namespace relpipe {
+namespace out {
+namespace x11 {
+
+using namespace relpipe;
+using namespace relpipe::reader;
+using namespace relpipe::reader::handlers;
+
+class X11Handler : public RelationalReaderStringHandler {
+private:
+	std::ostream& output;
+	Configuration& configuration;
+	const char QUOTE = '"';
+	std::wstring_convert<std::codecvt_utf8<wchar_t>> convertor; // TODO: probably not needed
+	std::vector<AttributeMetadata> firstAttributes;
+	integer_t valueCount = 0;
+public:
+
+	X11Handler(std::ostream& output, Configuration& configuration) : output(output), configuration(configuration) {
+	}
+
+	void startRelation(string_t name, std::vector<AttributeMetadata> attributes) override {
+		if (firstAttributes.empty()) {
+			firstAttributes = attributes;
+			if (configuration.writeHeader) for (auto attr : attributes) attribute(attr.getAttributeName());
+		} else {
+			throw std::logic_error("Only a single relation can be converted to the X11 format.");
+		}
+	}
+
+	void attribute(const string_t& value) override {
+		valueCount++;
+
+		if (value.size() > 0) {
+			output << QUOTE;
+			for (auto ch : convertor.to_bytes(value)) {
+				if (ch == QUOTE) output << QUOTE << QUOTE;
+				else output << ch;
+			}
+			output << QUOTE;
+		}
+
+		if (valueCount % firstAttributes.size()) {
+			output << ",";
+		} else {
+			output << "\r\n";
+			valueCount = 0;
+		}
+	}
+
+	void endOfPipe() {
+		output.flush();
+	}
+
+};
+
+}
+}
+}