Handle newline and tab with shift/ctrl modifiers correctly.

MC already has its own half-ready trick: when pasting with Shift-Insert,
using the X11 extension, the newline ("Enter" as mc calls it) with the
Shift modifier pressed gets converted to a "Return", and in the editor
the Return character inserts a non-indenting newline. This makes pasting
better in terminals not supporting bracketed paste, however, it has some
problems that this commit addresses:

  * Shift+newline gets this special treatment, but Ctrl+newline gets
    dropped. Hence e.g. when pasting in Gnome-terminal with Ctrl+Shift+V
    all the newlines will be missing. This commit adds the same
    non-indenting newline behavior to Ctrl+Newline and Ctrl+Shift+Newline.

  * The code forgets about Tab that also needs special treatment:

    - Most terminals send \e[Z on Shift+Tab, this is not handled by MC
      at all, moreover it causes a hang for about a second. This commit
      teaches this sequence to MC. This is especially useful when no X11
      is available, because there Ctrl+Tab is identical to Tab, so the
      backwards tab feature is not available. With this commit Shift+Tab
      becomes a backwards tab too on all terminals that emit \e[Z.

    - When pasting to the editor, Shift+Tab, Ctrl+Tab and Ctrl+Shift+Tab
      should all insert a tab for the same reason mentioned at the newline.

    - It would look inconsistent in the keymap files to have logical code
      such as "backtab" instead of "shift-tab" and friends, hence get rid
      of KEY_BTAB and use KEY_M_SHIFT | '\t' instead.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>

lib/tty/key.c

@@ -331,6 +331,7 @@ static key_define_t xterm_key_defines[] = {
     {KEY_M_SHIFT | KEY_M_CTRL | KEY_DOWN, ESC_STR "[1;6B", MCKEY_NOACTION},
     {KEY_M_SHIFT | KEY_M_CTRL | KEY_RIGHT, ESC_STR "[1;6C", MCKEY_NOACTION},
     {KEY_M_SHIFT | KEY_M_CTRL | KEY_LEFT, ESC_STR "[1;6D", MCKEY_NOACTION},
+    {KEY_M_SHIFT | '\t', ESC_STR "[Z", MCKEY_NOACTION},
 
     /* putty */
     {KEY_M_SHIFT | KEY_M_CTRL | KEY_UP, ESC_STR "[[1;6A", MCKEY_NOACTION},
@@ -1013,18 +1014,11 @@ correct_key_code (int code)
     if (c == KEY_SCANCEL)
         c = '\t';
 
-    /* Convert Shift+Tab and Ctrl+Tab to Back Tab
-     * only if modifiers directly from X11
-     */
-#ifdef HAVE_TEXTMODE_X11_SUPPORT
-    if (x11_window != 0)
-#endif /* HAVE_TEXTMODE_X11_SUPPORT */
+    /* Convert Back Tab to Shift+Tab */
+    if (c == KEY_BTAB)
     {
-        if ((c == '\t') && (mod & (KEY_M_SHIFT | KEY_M_CTRL)))
-        {
-            c = KEY_BTAB;
-            mod = 0;
-        }
+        c = '\t';
+        mod = KEY_M_SHIFT;
     }
 
     /* F0 is the same as F10 for out purposes */

lib/widget/dialog.c

@@ -493,7 +493,7 @@ dlg_key_event (WDialog * h, int d_key)
             dlg_one_down (h);
             return;
         }
-        else if (d_key == KEY_BTAB)
+        else if ((d_key & ~(KEY_M_SHIFT | KEY_M_CTRL)) == '\t')
         {
             dlg_one_up (h);
             return;

misc/mc.default.keymap

@@ -227,14 +227,14 @@ Right = right
 WordLeft = ctrl-left; ctrl-z
 WordRight = ctrl-right; ctrl-x
 Enter = enter
-Return = shift-enter
+Return = shift-enter; ctrl-enter; ctrl-shift-enter
 BackSpace = backspace; ctrl-h
 Delete = delete; ctrl-d
 PageUp = pgup
 PageDown = pgdn
 Home = home
 End = end
-Tab = tab
+Tab = tab; shift-tab; ctrl-tab; ctrl-shift-tab
 Undo = ctrl-u
 Redo = alt-r
 Top = ctrl-home; alt-lt

misc/mc.emacs.keymap

@@ -227,14 +227,14 @@ Right = right; ctrl-f
 WordLeft = ctrl-left; alt-b
 WordRight = ctrl-right; alt-f
 Enter = enter
-Return = shift-enter
+Return = shift-enter; ctrl-enter; ctrl-shift-enter
 BackSpace = backspace
 Delete = delete
 PageUp = pgup; alt-v
 PageDown = pgdn; ctrl-v
 Home = home; ctrl-a
 End = end; ctrl-e
-Tab = tab
+Tab = tab; shift-tab; ctrl-tab; ctrl-shift-tab
 Undo = ctrl-u
 # Redo =
 Top = ctrl-home; alt-lt

src/keybind-defaults.c

@@ -320,8 +320,8 @@ static const global_keymap_ini_t default_help_keymap[] = {
 #ifdef USE_INTERNAL_EDIT
 static const global_keymap_ini_t default_editor_keymap[] = {
     {"Enter", "enter"},
-    {"Return", "shift-enter"},  /* useful for pasting multiline text */
-    {"Tab", "tab"},
+    {"Return", "shift-enter; ctrl-enter; ctrl-shift-enter"},  /* useful for pasting multiline text */
+    {"Tab", "tab; shift-tab; ctrl-tab; ctrl-shift-tab"},  /* ditto */
     {"BackSpace", "backspace; ctrl-h"},
     {"Delete", "delete; ctrl-d"},
     {"Left", "left"},