aql: basic tab-completion using readline

please review before merging

alib2cli/src/environment/Environment.h

@@ -55,6 +55,16 @@ public:
 			throw exception::CommonException ( "Binded value of name " + name + " not found." );
 	}
+	const std::set < std::string > getBindingNames ( ) const {
+		std::set < std::string > res;
+
+		for ( const std::pair < const std::string, std::string > & kv : m_bindings ) {
+			res.insert ( kv.first );
+		}
+
+		return res;
+	}
+
 	void setBinding ( std::string name, std::string value ) {
 		m_bindings [ std::move ( name ) ] = std::move ( value );
 	}
@@ -75,6 +85,16 @@ public:
 		return ptr->getConstValueReference ( );
 	}
+	const std::set < std::string > getVariableNames ( ) const {
+		std::set < std::string > res;
+
+		for ( const std::pair < const std::string, std::shared_ptr < abstraction::OperationAbstraction > > & kv : m_variables ) {
+			res.insert ( kv.first );
+		}
+
+		return res;
+	}
+
 	void setVariable ( std::string name, std::shared_ptr < abstraction::OperationAbstraction > value ) {
 		setVariableInt ( std::move ( name ), std::move ( value ) );
 	}