use signal/slot for updating workspace instead of using event listener * main-window.h, main-window.cc: Clean up list of include files. (main_window::prepare_to_exit): Rename from prepare_to_quit. Change all uses. (main_window::update_workspace): Delete. (main_window::construct): Don't connect _octave_qt_event_listener:update_workspace_signal to main_window::update_workspace. (main_window::construct_octave_qt_link): Connect _octave_qt_link::set_workspace_signal to _workspace_model::set_workspace. Connect _octave_qt_link::clear_workspace_signal to _workspace_model::clear_workspace. * symbol-information.h, symbol-information.cc: Delete * libgui/src/module.mk (noinst_HEADERS, src_libgui_src_la_SOURCES): Remove them from the lists. * octave-qt-link.h, octave-qt-link.cc: Don't use symbol_information to store workspace info. (octave_qt_link::do_update_workspace): Delete. (octave_qt_link::do_set_workspace, octave_qt_link::do_clear_workspace): New functions. (octave_qt_link::do_pre_input_event): Don't call do_update_workspace. (octave_qt_link::set_workspace_signal, octave_qt_link::clear_workspace_signal): New signals. * workspace-model.h, workspace-model.cc: Don't use symbol_information to store workspace info. Accept workspace info through a signal/slot combination, not by asking the symbol table. (workspace_model::request_update_workspace, (workspace_model::update_workspace_callback): Delete. (workspace_model::set_workspace, workspace_model::clear_workspace, workspace_model::clear_data, workspace_model::clear_tree, workspace_model::update_tree, workspace_model::append_tree): New functions. * workspace-view.h, workspace-view.cc (workspace_view::model_changed): Don't call update_workspace_callback. The model now signals the view when it has changed. * input.cc (octave_base_reader::octave_gets, get_debug_input): Call octave_link::set_workspace just prior to prompting for input. * workspace-element.h: New file. * libinterp/interpfcn/module.mk (INTERPFCN_INC): Include it in the list. * octave-link.cc: Don't include symtab.h. * octave-link.h (octave_link::update_workspace): Delete. (octave_link::set_workspace, octave_link::do_set_workspace, * octave_link::clear_workspace, octave_link::do_clear_workspace): New functions. * symtab.h, symtab.cc (symbol_table::workspace_info, symbol_table::do_workspace_info): New functions. * ov.h (octave_value::short_disp): New function. * ov-base.h, ov-base.cc (octave_base_value::short_disp): New function. * ov-base-scalar.h, ov-base-scalar.cc (octave_base_scalar<ST>::short_disp): New function. * ov-range.h, ov-range.cc (octave_range::short_disp): New function.

--- a/libinterp/octave-value/ov-base.h
+++ b/libinterp/octave-value/ov-base.h
@@ -616,6 +616,8 @@
   print_with_name (std::ostream& output_buf, const std::string& name,
                    bool print_padding = true);
 
+  virtual std::string short_disp (void) const { return "..."; }
+
   virtual void print_info (std::ostream& os, const std::string& prefix) const;
 
   virtual bool save_ascii (std::ostream& os);