tabpage: track last-used tabpage #11626

In a multi-window scenario, it is possible to return focus to the last
accessed window via n_CTRL-W_p.  However, in the case of a multi-tab
scenario, there was previously no way to return focus to the last
accessed *tab*.  Here, that ability is added via n_g<tab>.

Additionally, the index of the previous tab is exposed via
tabpagenr('#'), mirroring the existing functionality of winnr('#').

1 files changed, 14 insertions, 6 deletions

diff --git a/src/nvim/normal.c b/src/nvim/normal.c
index 9c707a6fdc..d0b9fd4589 100644
--- a/src/nvim/normal.c
+++ b/src/nvim/normal.c
@@ -6312,9 +6312,7 @@ static void nv_gomark(cmdarg_T *cap)
   }
 }
 
-/*
- * Handle CTRL-O, CTRL-I, "g;" and "g," commands.
- */
+// Handle CTRL-O, CTRL-I, "g;", "g,", and "CTRL-Tab" commands.
 static void nv_pcmark(cmdarg_T *cap)
 {
   pos_T       *pos;
@@ -6322,11 +6320,16 @@ static void nv_pcmark(cmdarg_T *cap)
   const bool old_KeyTyped = KeyTyped;       // getting file may reset it
 
   if (!checkclearopq(cap->oap)) {
-    if (cap->cmdchar == 'g')
+    if (cap->cmdchar == TAB && mod_mask == MOD_MASK_CTRL) {
+      goto_tabpage_lastused();
+      return;
+    }
+    if (cap->cmdchar == 'g') {
       pos = movechangelist((int)cap->count1);
-    else
+    } else {
       pos = movemark((int)cap->count1);
-    if (pos == (pos_T *)-1) {           /* jump to other file */
+    }
+    if (pos == (pos_T *)-1) {           // jump to other file
       curwin->w_set_curswant = true;
       check_cursor();
     } else if (pos != NULL)                 /* can jump */
@@ -7059,6 +7062,11 @@ static void nv_g_cmd(cmdarg_T *cap)
     if (!checkclearop(oap))
       goto_tabpage(-(int)cap->count1);
     break;
+  case TAB:
+    if (!checkclearop(oap)) {
+      goto_tabpage_lastused();
+    }
+    break;
 
   case '+':
   case '-':   /* "g+" and "g-": undo or redo along the timeline */