Merge pull request #1701 from sakurawald/fix-self-insert-command-in-v…

…i-insert

fix: the self-insert command in vi-mode should not insert un-printable char while flushing the pending-keys

extensions/vi-mode/vi-mode.lisp

@@ -70,14 +70,29 @@
          (this-command-keys (vi-this-command-keys))
          (pending-keys (cdr this-command-keys)))
 
-    ;; For the command `self-insert`, the `this-command-keys` is typically only 1 char. (pending-keys = nil)
-    ;; If pending-keys is NOT nil, then these keys are used to disguish the keys between `self-insert` command and other commands. 
-    ;; For other commands, we can simply ignore the pending-keys.
-    ;; For self-insert command, we should also flusthese pending-keys.
+    ;; NOTE: In `vim`, if you define `jk` as `Escape` in insert-mode. The effect is:
+    ;; 1. In vi-insert-mode, press `j` and `k` will escape from insert-mode to normal-mode.
+    ;; 2. In vi-insert-mode, press `j` and `<second-key>` will:
+    ;;   a. If `<second-key>` is print-able-key, taken `e` key for example, then will self-insert `j` and self-insert `e`.
+    ;;   b. If `<second-key>` is un-print-able-key, taken `Backspace` key for example, then will cancel the self-insert `j` and remain in vi-insert-mode.
+
+    ;; FIXME: In `lem` impl, the `2.b` case will not cancel the self-insert of `j` key, because the code is written in post-command-hook, we have no chance to cancel the executing of `self-insert` command for the first-key.
+    ;;
+    ;;
+    ;;
+    ;; For self-insert command, we should also flush the pending-keys.
+    ;; 1. Typically, the length of`this-command-keys` is only 1 key. (pending-keys = nil)
+    ;; 2. If the length of `this-command-keys` > 1 key (pending-keys is not nil, they are used to disguish `self-insert` command and other commands), we need to flush `pending-keys`.
     (when (and
            (typep command 'self-insert)
            pending-keys)
-      (dolist (key pending-keys) (self-insert 1 (key-to-char key))))
+      (loop :for key :in pending-keys
+            ;; FIXME: the `named-key` is not identical to `print-able-key`. (Taken `Tab` key for example)
+            :until (named-key-sym-p (key-sym key))
+            :do 
+               (self-insert 1 (key-to-char key))))
+
+
 
     (when *enable-repeat-recording*
       (unless (or (and (typep command 'vi-command)