diff -r 5d1c556ff7db -r da114916734b src/Mode.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/Mode.h	Sun May 23 13:59:09 2021 +0200
@@ -0,0 +1,41 @@
+/**
+ * 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 <relpipe/common/type/typedefs.h>
+#include <relpipe/reader/handlers/AttributeMetadata.h>
+
+namespace relpipe {
+namespace tr {
+namespace infertypes {
+
+class Mode {
+protected:
+	shared_ptr<writer::RelationalWriter> relationalWriter;
+
+	Mode(shared_ptr<writer::RelationalWriter> relationalWriter) : relationalWriter(relationalWriter) {
+	}
+
+public:
+	virtual ~Mode() = default;
+	virtual void startRelation(const relpipe::common::type::StringX name, std::vector<relpipe::reader::handlers::AttributeMetadata> attributes) = 0;
+	virtual void attribute(const relpipe::common::type::StringX& value) = 0;
+};
+
+}
+}
+}