bindings: hard-bind the zap function to M-Del (Alt+Delete)

So that the function is available in a default setup.

Signed-off-by: Brand Huntsman <alpha@qzx.com>

doc/nano.texi

@@ -1161,6 +1161,7 @@ current cursor position.
 
 @item zap
 Throw away the current line (or the marked region).
+(This function is bound by default to <Meta+Delete>.)
 
 @item cutwordleft
 Cuts from the cursor position to the beginning of the preceding word.

doc/nanorc.5

@@ -512,6 +512,7 @@ current cursor position.
 .TP
 .B zap
 Throw away the current line (or the marked region).
+(This function is bound by default to <Meta+Delete>.)
 .TP
 .B cutwordleft
 Cuts from the cursor position to the beginning of the preceding word.

src/global.c

@@ -76,6 +76,7 @@ int shiftleft, shiftright, shiftup, shiftdown;
 int shiftcontrolleft, shiftcontrolright, shiftcontrolup, shiftcontroldown;
 int shiftcontrolhome, shiftcontrolend;
 int altleft, altright, altup, altdown;
+int altdelete;
 int shiftaltleft, shiftaltright, shiftaltup, shiftaltdown;
 #endif
 
@@ -1156,6 +1157,7 @@ void shortcut_init(void)
 	add_to_sclist(MMAIN, "M-E", 0, do_redo, 0);
 	add_to_sclist(MMAIN, "Sh-^Del", CONTROL_SHIFT_DELETE, do_cut_prev_word, 0);
 	add_to_sclist(MMAIN, "^Del", CONTROL_DELETE, do_cut_next_word, 0);
+	add_to_sclist(MMAIN, "M-Del", ALT_DELETE, zap_text, 0);
 #endif
 #ifdef ENABLE_WORDCOMPLETION
 	add_to_sclist(MMAIN, "^]", 0, complete_a_word, 0);

src/nano.c

@@ -2596,6 +2596,7 @@ int main(int argc, char **argv)
 	altright = get_keycode("kRIT3", ALT_RIGHT);
 	altup = get_keycode("kUP3", ALT_UP);
 	altdown = get_keycode("kDN3", ALT_DOWN);
+	altdelete = get_keycode("kDC3", ALT_DELETE);
 
 	shiftaltleft = get_keycode("kLFT4", SHIFT_ALT_LEFT);
 	shiftaltright = get_keycode("kRIT4", SHIFT_ALT_RIGHT);

src/nano.h

@@ -594,6 +594,7 @@ enum
 #define ALT_RIGHT 0x422
 #define ALT_UP 0x423
 #define ALT_DOWN 0x424
+#define ALT_DELETE 0x427
 #define SHIFT_ALT_LEFT 0x431
 #define SHIFT_ALT_RIGHT 0x432
 #define SHIFT_ALT_UP 0x433

src/proto.h

@@ -67,6 +67,7 @@ extern int shiftcontrolup, shiftcontroldown;
 extern int shiftcontrolhome, shiftcontrolend;
 extern int altleft, altright;
 extern int altup, altdown;
+extern int altdelete;
 extern int shiftaltleft, shiftaltright;
 extern int shiftaltup, shiftaltdown;
 #endif

src/winio.c

@@ -576,7 +576,10 @@ int parse_kbinput(WINDOW *win)
 		return ALT_UP;
 	else if (retval == altdown)
 		return ALT_DOWN;
-	else if (retval == shiftaltleft) {
+	else if (retval == altdelete) {
+		meta_key = TRUE;
+		return ALT_DELETE;
+	} else if (retval == shiftaltleft) {
 		shift_held = TRUE;
 		return KEY_HOME;
 	} else if (retval == shiftaltright) {
@@ -609,6 +612,11 @@ int parse_kbinput(WINDOW *win)
 		/* Are both Shift and Ctrl being held while Delete is pressed? */
 		if ((modifiers & 0x05) == 0x05 && retval == KEY_DC)
 			return CONTROL_SHIFT_DELETE;
+		/* Is Meta being held while Delete is pressed? */
+		if (modifiers == 0x08 && retval == KEY_DC) {
+			meta_key = TRUE;
+			return ALT_DELETE;
+		}
 #endif
 		/* Is Ctrl being held? */
 		if (modifiers & 0x04) {