Add support for backtab

Fixes #69

2 files changed, 13 insertions, 3 deletions

diff --git a/vterm-module.c b/vterm-module.c
index 02daed5..371c5b7 100644
--- a/vterm-module.c
+++ b/vterm-module.c
@@ -544,6 +544,8 @@ static void term_process_key(Term *term, unsigned char *key, size_t len,
     vterm_keyboard_end_paste(term->vt);
   } else if (is_key(key, len, "<tab>")) {
     vterm_keyboard_key(term->vt, VTERM_KEY_TAB, modifier);
+  } else if (is_key(key, len, "<backtab>") || is_key(key, len, "<iso-lefttab>")) {
+    vterm_keyboard_key(term->vt, VTERM_KEY_TAB, VTERM_MOD_SHIFT);
   } else if (is_key(key, len, "<backspace>")) {
     vterm_keyboard_key(term->vt, VTERM_KEY_BACKSPACE, modifier);
   } else if (is_key(key, len, "<escape>")) {
diff --git a/vterm.el b/vterm.el
index 43cd4e8..1ac9275 100644
--- a/vterm.el
+++ b/vterm.el
@@ -163,6 +163,7 @@ for different shell"
 
 ;; Keybindings
 (define-key vterm-mode-map [tab]                       #'vterm--self-insert)
+(define-key vterm-mode-map [backtab]                   #'vterm--self-insert)
 (define-key vterm-mode-map [backspace]                 #'vterm--self-insert)
 (define-key vterm-mode-map [M-backspace]               #'vterm--self-insert)
 (define-key vterm-mode-map [return]                    #'vterm--self-insert)
@@ -194,6 +195,15 @@ for different shell"
                                        unless (member key vterm-keymap-exceptions)
                                        collect key))))
 
+(defun vterm-event-basic-type (event)
+  "Same as `event-basic-type', except the downcasing of EVENT."
+  (if (consp event)
+      (setq event (car event)))
+  (if (symbolp event)
+      (car (get event 'event-symbol-elements))
+    (let* ((base (logand event (1- ?\A-\^@))))
+      (if (< base 32) (logior base 64) base))))
+
 (defun vterm--self-insert ()
   "Sends invoking key to libvterm."
   (interactive)
@@ -202,7 +212,7 @@ for different shell"
            (shift (memq 'shift modifiers))
            (meta (memq 'meta modifiers))
            (ctrl (memq 'control modifiers)))
-      (when-let ((key (key-description (vector (event-basic-type last-input-event)))))
+      (when-let ((key (key-description (vector (vterm-event-basic-type last-input-event)))))
         (vterm-send-key key shift meta ctrl)))))
 
 (defun vterm-send-key (key &optional shift meta ctrl)
@@ -210,8 +220,6 @@ for different shell"
   (when vterm--term
     (let ((inhibit-redisplay t)
           (inhibit-read-only t))
-      (when (and shift (not meta) (not ctrl))
-        (setq key (upcase key)))
       (vterm--update vterm--term key shift meta ctrl))))
 
 (defun vterm-send-ctrl-c ()