gdb: move some commands into the tui namespace

There are a lot of tui related commands that live in the top-level
command name space, e.g. layout, focus, refresh, winheight.

Having them at the top level means less typing for the user, which is
good, but, I think, makes command discovery harder.

In this commit, I propose moving all of the above mentioned commands
into the tui namespace, so 'layout' becomes 'tui layout', etc.  But I
will then add aliases so that the old commands will still work,
e.g. I'll make 'layout' an alias for 'tui layout'.

The benefit I see in this work is that tui related commands can be
more easily discovered by typing 'tui ' and then tab-completing.  Also
the "official" command is now a tui-sub-command, this is visible in,
for example, the help output, e.g.:

  (gdb) help layout
  tui layout, layout
  Change the layout of windows.
  Usage: tui layout prev | next | LAYOUT-NAME

  List of tui layout subcommands:

  tui layout asm -- Apply the "asm" layout.
  tui layout next -- Apply the next TUI layout.
  tui layout prev -- Apply the previous TUI layout.
  tui layout regs -- Apply the TUI register layout.
  tui layout split -- Apply the "split" layout.
  tui layout src -- Apply the "src" layout.

Which I think is a good thing, it makes it clearer that this is a tui
command.

I've added a NEWS entry and updated the docs to mention the new and
old command names, with the new name being mentioned first.

2 files changed, 45 insertions, 11 deletions

diff --git a/gdb/tui/tui-layout.c b/gdb/tui/tui-layout.c
index 6195ca1..04e5ac2 100644
--- a/gdb/tui/tui-layout.c
+++ b/gdb/tui/tui-layout.c
@@ -839,6 +839,14 @@ destroy_layout (struct cmd_list_element *self, void *context)
 
 static struct cmd_list_element *layout_list;
 
+/* Called to implement 'tui layout'.  */
+
+static void
+tui_layout_command (const char *args, int from_tty)
+{
+  help_list (layout_list, "tui layout ", all_commands, gdb_stdout);
+}
+
 /* Add a "layout" command with name NAME that switches to LAYOUT.  */
 
 static struct cmd_list_element *
@@ -1017,10 +1025,12 @@ void _initialize_tui_layout ();
 void
 _initialize_tui_layout ()
 {
-  add_basic_prefix_cmd ("layout", class_tui, _("\
+  struct cmd_list_element *layout_cmd
+    = add_prefix_cmd ("layout", class_tui, tui_layout_command, _("\
 Change the layout of windows.\n\
-Usage: layout prev | next | LAYOUT-NAME"),
-			&layout_list, 0, &cmdlist);
+Usage: tui layout prev | next | LAYOUT-NAME"),
+		      &layout_list, 0, tui_get_cmd_list ());
+  add_com_alias ("layout", layout_cmd, class_tui, 0);
 
   add_cmd ("next", class_tui, tui_next_layout_command,
 	   _("Apply the next TUI layout."),
diff --git a/gdb/tui/tui-win.c b/gdb/tui/tui-win.c
index b95d72d..1371861 100644
--- a/gdb/tui/tui-win.c
+++ b/gdb/tui/tui-win.c
@@ -977,6 +977,18 @@ parse_scrolling_args (const char *arg,
     }
 }
 
+/* The list of 'tui window' sub-commands.  */
+
+static cmd_list_element *tui_window_cmds = nullptr;
+
+/* Called to implement 'tui window'.  */
+
+static void
+tui_window_command (const char *args, int from_tty)
+{
+  help_list (tui_window_cmds, "tui window ", all_commands, gdb_stdout);
+}
+
 /* Function to initialize gdb commands, for tui window
    manipulation.  */
 
@@ -995,8 +1007,11 @@ _initialize_tui_win ()
 			  &tui_setlist, &tui_showlist,
 			  &setlist, &showlist);
 
-  add_com ("refresh", class_tui, tui_refresh_all_command,
-	   _("Refresh the terminal display."));
+  cmd_list_element *refresh_cmd
+    = add_cmd ("refresh", class_tui, tui_refresh_all_command,
+	       _("Refresh the terminal display."),
+	       tui_get_cmd_list ());
+  add_com_alias ("refresh", refresh_cmd, class_tui, 0);
 
   cmd_list_element *tabset_cmd
     = add_com ("tabset", class_tui, tui_set_tab_width_command, _("\
@@ -1004,21 +1019,30 @@ Set the width (in characters) of tab stops.\n\
 Usage: tabset N"));
   deprecate_cmd (tabset_cmd, "set tui tab-width");
 
+  /* Setup the 'tui window' list of command.  */
+  add_prefix_cmd ("window", class_tui, tui_window_command,
+		  _("Text User Interface window commands."),
+		  &tui_window_cmds, 1, tui_get_cmd_list ());
+
   cmd_list_element *winheight_cmd
-    = add_com ("winheight", class_tui, tui_set_win_height_command, _("\
+    = add_cmd ("height", class_tui, tui_set_win_height_command, _("\
 Set or modify the height of a specified window.\n\
-Usage: winheight WINDOW-NAME [+ | -] NUM-LINES\n\
-Use \"info win\" to see the names of the windows currently being displayed."));
+Usage: tui window height WINDOW-NAME [+ | -] NUM-LINES\n\
+Use \"info win\" to see the names of the windows currently being displayed."),
+	       &tui_window_cmds);
+  add_com_alias ("winheight", winheight_cmd, class_tui, 0);
   add_com_alias ("wh", winheight_cmd, class_tui, 0);
   set_cmd_completer (winheight_cmd, winheight_completer);
   add_info ("win", tui_all_windows_info,
 	    _("List of all displayed windows.\n\
 Usage: info win"));
   cmd_list_element *focus_cmd
-    = add_com ("focus", class_tui, tui_set_focus_command, _("\
+    = add_cmd ("focus", class_tui, tui_set_focus_command, _("\
 Set focus to named window or next/prev window.\n\
-Usage: focus [WINDOW-NAME | next | prev]\n\
-Use \"info win\" to see the names of the windows currently being displayed."));
+Usage: tui focus [WINDOW-NAME | next | prev]\n\
+Use \"info win\" to see the names of the windows currently being displayed."),
+	       tui_get_cmd_list ());
+  add_com_alias ("focus", focus_cmd, class_tui, 0);
   add_com_alias ("fs", focus_cmd, class_tui, 0);
   set_cmd_completer (focus_cmd, focus_completer);
   add_com ("+", class_tui, tui_scroll_forward_command, _("\