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.h	Sat Jun 19 10:33:37 2021 -0400
+++ b/libinterp/corefcn/event-manager.h	Sat Jun 19 14:34:07 2021 -0400
@@ -148,6 +148,8 @@
 
     virtual void apply_preferences (void) { }
 
+    virtual void show_terminal_window (void) { }
+
     virtual bool show_documentation (const std::string& /*file*/)
     {
       return false;
@@ -454,6 +456,12 @@
         return false;
     }
 
+    void show_terminal_window (void)
+    {
+      if (enabled ())
+        instance->show_terminal_window ();
+    }
+
     bool show_documentation (const std::string& file)
     {
       return enabled () ? instance->show_documentation (file) : false;