[Nano-devel] [PATCH] input: ignore any <Escape>s before a valid command keystroke

[Benno Schulenberg]

Just like an <Esc> before a Ctrl+letter keystroke is ignored, an <Esc>
before an Alt+letter keystroke should be ignored too -- it should not
be interpreted as if the user had typed <Esc> <Esc> letter.


[The trigger for this patch was that during my vacation I played with some
other editors, and in all of them a valid Ctrl+X or Alt+X keystroke would
fail to work if I had pressed <Esc> beforehand -- and one had to press
<Esc> sometimes, to discard a menu for example, so this happened quite
a lot.  It was majorly frustrating.]

---
 src/winio.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/src/winio.c b/src/winio.c
index 281488a8..613beb3c 100644
--- a/src/winio.c
+++ b/src/winio.c
@@ -385,7 +385,7 @@ int parse_kbinput(WINDOW *win)
                if (escapes > 3)
                        escapes = 1;
                /* Take note when an Esc arrived by itself. */
-               solitary = (escapes == 1 && key_buffer_len == 0);
+               solitary = (key_buffer_len == 0);
                return ERR;
        }
 
@@ -476,12 +476,13 @@ int parse_kbinput(WINDOW *win)
                                        }
                                } else {
                                        if (digit_count == 0)
-                                               /* Two escapes followed by a 
non-decimal
-                                                * digit (or a decimal digit 
that would
-                                                * create a byte sequence 
greater than 2XX)
-                                                * and there aren't any other 
codes waiting:
-                                                * control character sequence 
mode. */
-                                               retval = 
get_control_kbinput(keycode);
+                                               /* Two escapes followed by a 
non-digit: meta key
+                                                * or control character 
sequence mode. */
+                                               if (!solitary) {
+                                                       meta_key = TRUE;
+                                                       retval = keycode;
+                                               } else
+                                                       retval = 
get_control_kbinput(keycode);
                                        else {
                                                /* An invalid digit in the 
middle of a byte
                                                 * sequence: reset the byte 
sequence counter
@@ -505,11 +506,13 @@ int parse_kbinput(WINDOW *win)
                        }
                        break;
                case 3:
-                       if (key_buffer_len == 0)
+                       if (key_buffer_len == 0) {
+                               if (!solitary)
+                                       meta_key = TRUE;
                                /* Three escapes followed by a non-escape, and 
no
                                 * other codes are waiting: normal input mode. 
*/
                                retval = keycode;
-                       else
+                       } else
                                /* Three escapes followed by a non-escape, and 
more
                                 * codes are waiting: combined control 
character and
                                 * escape sequence mode.  First interpret the 
escape
-- 
2.17.1