Add functions to show GUI windows (bug #57213) * event-manager.h (interpreter_events::focus_window): New empty method. (event_manager::focus_window): New vistual method that executes the instance's focus_window method. * event_manager.cc (commandwindow, commandhistory, filebrowser, workspace): New builtin interpreter functions. * qt-interpreter-events.[h, cc] (qt_interpreter_events::focus_window_signal): New signal. (qt_interpreter_events::focus_window): Implements event_manager::focus_window, emits focus_window_signal. * main-window.[h, cc] (main_window::focus_window): New slot that activates the named window. * octave-qobject.cc (gui_qobject::gui_qobject): Connect qt_interpreter_events::focus_window_signal to main_window::focus_window. * __unimplemented__.m: Remove commandwindow, commandhistory, filebrowser, and workspace from the list. * gui.txi: Add commandwindow, commandhistory, filebrowser, workspace docstrings.

--- a/libgui/src/qt-interpreter-events.h	Mon Nov 11 20:22:52 2019 +0100
+++ b/libgui/src/qt-interpreter-events.h	Tue Nov 12 14:54:25 2019 +0100
@@ -132,6 +132,8 @@
 
     bool copy_image_to_clipboard (const std::string& file);
 
+    void focus_window (const std::string win_name);
+
     void execute_command_in_terminal (const std::string& command);
 
     void register_doc (const std::string& file);
@@ -191,6 +193,8 @@
 
     void copy_image_to_clipboard_signal (const QString& file, bool remove_file);
 
+    void focus_window_signal (const QString& win_name);
+
     void edit_file_signal (const QString& file);
 
     void directory_changed_signal (const QString& dir);