From 0c844c3e9a8e72bd83e370c12eda5cb315ac5d41 Mon Sep 17 00:00:00 2001
From: Yuchen Pei <id@ypei.org>
Date: Sat, 19 Aug 2023 22:39:27 +1000
Subject: improve delete-pair related functions

---
 emacs/.emacs.d/init/ycp-editing.el   |  5 ++-
 emacs/.emacs.d/lisp/my/my-editing.el | 65 ++++++++++++++++++++++++++++++++++++
 2 files changed, 69 insertions(+), 1 deletion(-)

diff --git a/emacs/.emacs.d/init/ycp-editing.el b/emacs/.emacs.d/init/ycp-editing.el
index c53cf74..5634f86 100644
--- a/emacs/.emacs.d/init/ycp-editing.el
+++ b/emacs/.emacs.d/init/ycp-editing.el
@@ -55,10 +55,13 @@
   ;; call to `kill-visual-line' etc. when `visual-line-mode' is on.
   (advice-add 'kill-visual-line :override 'kill-line)
   (advice-add 'beginning-of-visual-line :override 'beginning-of-line)
-  (advice-add 'end-of-visual-line :override 'end-of-line))
+  (advice-add 'end-of-visual-line :override 'end-of-line)
+  (setq delete-pair-blink-delay 0)
+  )
 
 (my-package my-editing
   (:delay 5)
+  (my-override delete-pair)
   (my-keybind global-map
     "C-k" #'my-kill-line
     "M-k" #'my-kill-line-backward
diff --git a/emacs/.emacs.d/lisp/my/my-editing.el b/emacs/.emacs.d/lisp/my/my-editing.el
index 6bbde62..f8e405e 100644
--- a/emacs/.emacs.d/lisp/my/my-editing.el
+++ b/emacs/.emacs.d/lisp/my/my-editing.el
@@ -302,6 +302,71 @@ controlled by `delete-pair-blink-delay'."
       (delete-pair -1)
     (delete-pair 1)))
 
+(defun my-delete-line-if-space-only ()
+  "Delete the current line, if it has only space and nothing else."
+  (interactive)
+  (save-excursion
+    (beginning-of-line)
+    (when (looking-at-p "^\\ *$")
+      (delete-line))))
+
+;;; To override delete-pair
+(defun my-delete-pair (&optional arg)
+  "Delete a pair of characters enclosing ARG sexps that follow point.
+
+A negative ARG deletes a pair around the preceding ARG sexps
+instead. The option `delete-pair-blink-delay' can disable
+blinking.
+
+Delete space-only-lines caused by the deletion, as well as
+re-indent the affected region."
+  (interactive "P")
+  (if arg
+      (setq arg (prefix-numeric-value arg))
+    (setq arg 1))
+  (let ((beg) (end))
+    (if (< arg 0)
+        (save-excursion
+	        (skip-chars-backward " \t")
+	        (save-excursion
+	          (let ((close-char (char-before)))
+	            (forward-sexp arg)
+	            (unless (member (list (char-after) close-char)
+			                        (mapcar (lambda (p)
+				                                (if (= (length p) 3) (cdr p) p))
+				                              insert-pair-alist))
+	              (error "Not after matching pair"))
+	            (when (and (numberp delete-pair-blink-delay)
+		                     (> delete-pair-blink-delay 0))
+	              (sit-for delete-pair-blink-delay))
+	            (delete-char 1)
+              (my-delete-line-if-space-only)
+              (setq beg (point))))
+	        (delete-char -1)
+          (my-delete-line-if-space-only)
+          (setq end (point)))
+      (save-excursion
+        (skip-chars-forward " \t")
+        (save-excursion
+	        (let ((open-char (char-after)))
+	          (forward-sexp arg)
+	          (unless (member (list open-char (char-before))
+			                      (mapcar (lambda (p)
+				                              (if (= (length p) 3) (cdr p) p))
+				                            insert-pair-alist))
+	            (error "Not before matching pair"))
+	          (when (and (numberp delete-pair-blink-delay)
+		                   (> delete-pair-blink-delay 0))
+	            (sit-for delete-pair-blink-delay))
+	          (delete-char -1)
+            (my-delete-line-if-space-only)
+            (setq end (point))))
+        (delete-char 1)
+        (my-delete-line-if-space-only)
+        (setq beg (point))))
+    (when (and beg end)
+      (indent-region beg end))))
+
 ;;;###autoload
 (defun my-zap-back-to-char (char &optional arg)
   "Backward `zap-to-char' for CHAR.
-- 
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