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diff --git a/libs/evoral/evoral/Parameter.h b/libs/evoral/evoral/Parameter.h
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+/*
+ * Copyright (C) 2008-2016 David Robillard <d@drobilla.net>
+ * Copyright (C) 2008-2018 Paul Davis <paul@linuxaudiosystems.com>
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef EVORAL_PARAMETER_HPP
+#define EVORAL_PARAMETER_HPP
+
+#include <string>
+#include <map>
+#include <stdint.h>
+#include <boost/shared_ptr.hpp>
+
+#include "evoral/visibility.h"
+#include "evoral/types.h"
+
+namespace Evoral {
+
+/** ID of a [play|record|automate]able parameter.
+ *
+ * A parameter is defined by (type, id, channel).  Type is an integer which
+ * can be used in any way by the application (e.g. cast to a custom enum,
+ * map to/from a URI, etc).  ID is type specific (e.g. MIDI controller #).
+ *
+ * This class defines a < operator which is a strict weak ordering, so
+ * Parameter may be stored in a std::set, used as a std::map key, etc.
+ */
+class LIBEVORAL_API Parameter
+{
+public:
+	inline Parameter(ParameterType type, uint8_t channel=0, uint32_t id=0)
+		: _type(type), _id(id), _channel(channel)
+	{}
+
+	inline ParameterType type()    const { return _type; }
+	inline uint8_t       channel() const { return _channel; }
+	inline uint32_t      id()      const { return _id; }
+
+	/** Equivalence operator
+	 * It is obvious from the definition that this operator
+	 * is transitive, as required by stict weak ordering
+	 * (see: http://www.sgi.com/tech/stl/StrictWeakOrdering.html)
+	 */
+	inline bool operator==(const Parameter& id) const {
+		return (_type == id._type && _channel == id._channel && _id == id._id );
+	}
+
+	inline bool operator!=(const Parameter& id) const {
+		return !operator==(id);
+	}
+
+	/** Strict weak ordering
+	 * See: http://www.sgi.com/tech/stl/StrictWeakOrdering.html
+	 * Sort Parameters first according to type then to channel and lastly to ID.
+	 */
+	inline bool operator<(const Parameter& other) const {
+		if (_type < other._type) {
+			return true;
+		} else if (_type == other._type && _channel < other._channel) {
+			return true;
+		} else if (_type == other._type && _channel == other._channel && _id < other._id ) {
+			return true;
+		}
+
+		return false;
+	}
+
+	inline operator bool() const { return (_type != 0); }
+
+private:
+	ParameterType _type;
+	uint32_t      _id;
+	uint8_t       _channel;
+};
+
+} // namespace Evoral
+
+namespace std {
+std::ostream& operator<< (std::ostream &str, Evoral::Parameter const &);
+}
+
+#endif // EVORAL_PARAMETER_HPP
+