m_output.println("Derivation history is "+(m_forwardingOn ? "on" : "off")+".");
}
protected void registerCommands() {
registerCommand(new ActiveNodesCommand(this));
registerCommand(new AgainCommand(this));
registerCommand(new BreakpointTimeCommand(this));
registerCommand(new ClearCommand(this));
registerCommand(new ContinueCommand(this));
registerCommand(new DerivationTreeCommand(this));
registerCommand(new ExitCommand(this));
registerCommand(new ForeverCommand(this));