Implement basic tab completion in navigate.

It doesn't work super well and it's missing set number
completion, but it's a step forward.

include/dindexer-common/readline_wrapper.hpp

@@ -0,0 +1,43 @@
+/* Copyright 2015, 2016, Michele Santullo
+ * This file is part of "dindexer".
+ *
+ * "dindexer" 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 3 of the License, or
+ * (at your option) any later version.
+ *
+ * "dindexer" 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 "dindexer".  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef id4DDE1979258D40A2973E2FC2AC3DF854
+#define id4DDE1979258D40A2973E2FC2AC3DF854
+
+#include <string>
+#include <vector>
+#include <functional>
+
+namespace dinlib {
+	class ReadlineWrapper {
+	public:
+		using MatchesCallback = std::function<std::vector<std::string>(const std::string&)>;
+
+		explicit ReadlineWrapper ( MatchesCallback parMatchesCallback );
+		~ReadlineWrapper ( void ) noexcept;
+
+		std::string read ( const std::string& parMessage ) const;
+		const std::vector<std::string>& matches ( const std::string& parPrefix ) const;
+
+	private:
+		mutable std::string m_last_prefix;
+		mutable std::vector<std::string> m_last_matches;
+		MatchesCallback m_fetch_matches;
+	};
+} //namespace dinlib
+
+#endif