allow terminal window to be opened from command line * command-widget.h, command-widget.cc (command_widget::update_prompt): New slot. (command_widget::insert_interpreter_output): Now public. (command_widget::command_widget): Don't connect to signals from parent object here. * octave-qobject.h, octave-qobject.cc (base_qobject::m_terminal_widget): New data member. (base_qobject::terminal_widget): New function. Make (command_widget, QTerminal)/base_qobject signal/slot connections here instead of in main_window constructor. (base_qobject::show_terminal_window): New slot. (base_qobject::base_qobject): Connect qt_interpreter_events::show_terminal_window_signal to base_qobject::show_terminal_window slot. (base_qobject::~base_qobject): Close and delete terminal widget. * main-window.h, main-window.cc (main_window::main_window): Acquire m_command_window from base_qobject instead of constructing here. * terminal-dock-widget.cc (terminal_dock_widget::terminal_dock_widget): Make dock widget/terminal widget signal/slot connections here instead of in main window constructor. Call make_window if parent object is nullptr. * event-manager.h, event-manager.cc (F__event_manager_show_terminal_window__): New function. (interpreter_events::show_terminal_window): New virtual function. (event_manager::show_terminal_window): New function. * qt-interpreter-events.h, qt-interpreter-events.cc (qt_interpreter_events::show_terminal_window): New signal (qt_interpreter_events::show_terminal_window): New function.

--- a/libinterp/corefcn/event-manager.cc	Sat Jun 19 10:33:37 2021 -0400
+++ b/libinterp/corefcn/event-manager.cc	Sat Jun 19 14:34:07 2021 -0400
@@ -619,6 +619,21 @@
 %!error <NAME must be a string> openvar (1:10)
 */
 
+DEFMETHOD (__event_manager_show_terminal_window__, interp, , ,
+           doc: /* -*- texinfo -*-
+@deftypefn {} {} __event_manager_show_terminal_window__ ()
+Undocumented internal function.
+@end deftypefn */)
+{
+  std::string file;
+
+  octave::event_manager& evmgr = interp.get_event_manager ();
+
+  evmgr.show_terminal_window ();
+
+  return ovl ();
+}
+
 DEFMETHOD (__event_manager_show_documentation__, interp, args, ,
            doc: /* -*- texinfo -*-
 @deftypefn {} {} __event_manager_show_documentation__ (@var{filename})