rewrite vterm-goto-char

vterm.el

@@ -1117,30 +1117,66 @@ It will reset to original position if it can't move there."
   (when (and vterm--term
              (vterm-cursor-in-command-buffer-p)
              (vterm-cursor-in-command-buffer-p pos))
-    (let ((moved t)
-          (origin-point (point))
-          pt cursor-pos succ)
-      (vterm-reset-cursor-point)
-      (setq cursor-pos (point))
-      (setq pt cursor-pos)
-      (while (and (> pos pt) moved)
-        (vterm-send-key "<right>" nil nil nil t)
-        (setq moved (not (= pt (point))))
-        (setq pt (point)))
-      (setq pt (point))
-      (setq moved t)
-      (while (and (< pos pt) moved)
-        (vterm-send-key "<left>" nil nil nil t)
-        (setq moved (not (= pt (point))))
-        (setq pt (point)))
-      (setq succ (= pos (point)))
-      (unless succ
-        (vterm-goto-char cursor-pos)
-        (goto-char origin-point))
-      succ)))
+    (vterm-reset-cursor-point)
+    (let ((diff (- pos (point))))
+      (= diff (vterm--forward-char diff)))))
 
 ;;; Internal
 
+(defun vterm--forward-char (&optional n)
+  "Move point N characters forward (backward if N is negative).
+
+Return the count of moved characeters,
+the returned value is negative when backward."
+  (vterm-reset-cursor-point)
+  (unless n (setq n 1))
+  (if (< n 0)
+      (- (vterm--backward-char (- n)))
+    (let ((pt (point))
+          (origin-pt (point))
+          (count 0)
+          (moved t))
+      (while (and moved (< count n))
+        (vterm-send-key "<right>" nil nil nil t)
+        (cond
+         ((= (point) (1+ pt))
+          (setq count (1+ count))
+          (setq pt (1+ pt)))
+         ((and (= (point) (+ 4 pt))
+               (looking-back (regexp-quote "^[[C"))) ;escape code for <right>
+          (dotimes (_ 3) (vterm-send-key "<backspace>" nil nil nil t)) ;;delete  "^[[C"
+          (setq moved nil))
+         ((> (point) (1+ pt))             ;auto suggest
+          (vterm-send-key "_" nil nil t t) ;undo C-_
+          (setq moved nil)
+          )
+         (t (setq moved nil))))
+      count)))
+
+(defun vterm--backward-char (&optional n)
+  "Move point N characters backward.
+
+Return count of moved characeters."
+  (vterm-reset-cursor-point)
+  (unless n (setq n 1))
+  (let ((pt (point))
+        (origin-pt (point))
+        (count 0)
+        (moved t))
+    (while (and moved (< count n))
+      (vterm-send-key "<left>" nil nil nil t)
+      (cond
+       ((= (point) (1- pt))
+        (setq count (1+ count))
+        (setq pt (1- pt))
+        )
+       ((and (= (point) (+ 4 pt))
+             (looking-back (regexp-quote "^[[D"))) ;escape code for <left>
+        (dotimes (_ 3) (vterm-send-key "<backspace>" nil nil nil t)) ;;delete  "^[[D"
+        (setq moved nil))
+       (t (setq moved nil))))
+    count))
+
 (defun vterm--delete-region(start end)
   "A wrapper for `delete-region'."
   (funcall vterm--delete-region-function start end))