From c6b9e2980aedb8b629ea111c1fa5b2409787fdf4 Mon Sep 17 00:00:00 2001
From: John Lorentzson <john_lorentzson@yahoo.com>
Date: Fri, 18 Jul 2025 17:53:47 +0200
Subject: [PATCH] Optimize editor's character-in-line insertion

---
 wip-duuqnd/editor/editor.lisp | 38 +++++++++++++++++++++--------------
 1 file changed, 23 insertions(+), 15 deletions(-)

diff --git a/wip-duuqnd/editor/editor.lisp b/wip-duuqnd/editor/editor.lisp
index 58b65b4..c5426de 100644
--- a/wip-duuqnd/editor/editor.lisp
+++ b/wip-duuqnd/editor/editor.lisp
@@ -315,7 +315,9 @@ serial connection the editor normally runs under.")
            (incf (fill-pointer (line-content line)))
            (replace (line-content line) to-shove
                     :start1 (1+ column))
-           (setf (char (line-content line) column) character)))))
+           (setf (char (line-content line) column) character))))
+  (when (line-in-view line (current-view *editor*))
+    (redisplay-line line :start column)))
 
 (defmethod delete-character-in-line ((line line) column)
   (unless (< column (fill-pointer (line-content line)))
@@ -365,23 +367,27 @@ serial connection the editor normally runs under.")
                  (cursor-column (cursor *editor*)) start)
            (update-buffer-cursor (current-buffer *editor*))))))
 
-(defmethod redisplay-line ((line line))
+(defmethod redisplay-line ((line line) &key (start 0))
   ;; TODO: save the cursor position
   (with-editor-accessors *editor* (:current-line current
                                    :current-buffer buffer)
-    (move-cursor (view-line-number (buffer-view buffer) line) 0)
-    (write-char #\Return *eio*)
-    (write-byte #x1B *eio*)
-    (write-char #\[ *eio*)
-    (write-char #\K *eio*)
-    (write-string (line-content line) *eio*)
-    (update-buffer-cursor buffer))
+    (cond
+      ((= start (1- (line-length line)))
+       (let ((char-pos (1- (fill-pointer (line-content line)))))
+         (move-cursor (view-line-number (buffer-view buffer) line) char-pos)
+         (write-char (aref (line-content line) char-pos) *eio*)
+         (update-buffer-cursor buffer)))
+      (t
+       (hide-cursor)
+       (move-cursor (view-line-number (buffer-view buffer) line) start)
+       (write-byte #x1B *eio*)
+       (write-char #\[ *eio*)
+       (write-char #\K *eio*)
+       (write-string (line-content line) *eio* :start start)
+       (update-buffer-cursor buffer)
+       (show-cursor))))
   (force-output *eio*))
 
-(defun save-cursor ())
-
-(defun restore-cursor ())
-
 
 
 (defclass buffer ()
@@ -485,6 +491,9 @@ Additionally ensures correct line numbers on the way, as a bonus."
         :when (eql line view-line)
           :return number))
 
+(defmethod line-in-view ((line line) (view buffer-view))
+  (not (null (view-line-number view line))))
+
 (defmethod redisplay-view ((view buffer-view))
   (clear-screen)
   (do-view-lines (line number) view
@@ -547,8 +556,7 @@ Additionally ensures correct line numbers on the way, as a bonus."
         (progn
           (insert-character-into-line line column char)
           (incf column))
-        (feep))
-    (redisplay-line line)))
+        (feep))))
 
 (defun com-forward-delete ()
   ;; TODO: Check for end of line