[PATCH v3] git-gui: Handle Ctrl + BS/Del in the commit msg

[Ismael Luceno <ismael@iodev.co.uk>]

From: Ismael Luceno <ismael.luceno@tttech-auto.com>

- Control+BackSpace: Delete word to the left of the cursor.
- Control+Delete   : Delete word to the right of the cursor.

Originally introduced by BRIEF and Turbo Vision between 1985 and 1992,
they were adopted by most CUA-Compliant UIs, including those of: OS/2,
Windows, Mac OS, Qt, GTK, Open/Libre Office, Gecko, and GNU Emacs.

In both cases Tk already implements the functionality bound to other key
combination, so we use that.

Graphical examples:

Deleting to the left:
        v------ pointer
X_WORD____X
  ^-----^------ selection

Deleting to the right:
  v--------- pointer
X_WORD_X
  ^--^------ selection

Signed-off-by: Ismael Luceno <ismael.luceno@tttech-auto.com>

---
I'm re-submitting the patch after >1 year.

CC: Junio C Hamano <gitster@pobox.com>
CC: "brian m. carlson" <sandals@crustytoothpaste.net>
CC: Pat Thoyts <patthoyts@users.sourceforge.net>
CC: Johannes Schindelin <Johannes.Schindelin@gmx.de>

Notes:
    Changes since v2:
    - Reimplemented via existing events, which correctly delete spaces.
    - Further improved commit message.
    
    Changes since v1:
    - Improved commit message.

 git-gui/git-gui.sh | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/git-gui/git-gui.sh b/git-gui/git-gui.sh
index 6de74ce639..c4e0270626 100755
--- a/git-gui/git-gui.sh
+++ b/git-gui/git-gui.sh
@@ -3812,6 +3812,8 @@ bind $ui_comm <$M1B-Key-KP_Subtract> {show_less_context;break}
 bind $ui_comm <$M1B-Key-equal> {show_more_context;break}
 bind $ui_comm <$M1B-Key-plus> {show_more_context;break}
 bind $ui_comm <$M1B-Key-KP_Add> {show_more_context;break}
+bind $ui_comm <Control-Key-BackSpace> {event generate %W <Meta-Delete>;break}
+bind $ui_comm <Control-Key-Delete> {event generate %W <Meta-d>;break}
 
 bind $ui_diff <$M1B-Key-x> {tk_textCopy %W;break}
 bind $ui_diff <$M1B-Key-X> {tk_textCopy %W;break}
-- 
2.19.1