Better electric-pair-mode

better-electric-pair.el

(defun electric-pair-post-self-insert-function ()
  (let* ((syntax (and (eq (char-before) last-command-event) ; Sanity check.
		      (electric-pair-syntax last-command-event)))
         ;; FIXME: when inserting the closer, we should maybe use
         ;; self-insert-command, although it may prove tricky running
         ;; post-self-insert-hook recursively, and we wouldn't want to trigger
         ;; blink-matching-open.
         (closer (if (eq syntax ?\()
                     (cdr (or (assq last-command-event electric-pair-pairs)
                              (aref (syntax-table) last-command-event)))
                   last-command-event)))
    (cond
     ;; Wrap a pair around the active region.
     ((and (memq syntax '(?\( ?\" ?\$)) (use-region-p))
      (if (> (mark) (point))
          (goto-char (mark))
	;; We already inserted the open-paren but at the end of the
	;; region, so we have to remove it and start over.
	(delete-char -1)
	(save-excursion
          (goto-char (mark))
	  ;; Do not insert after `save-excursion' marker (Bug#11520).
          (insert-before-markers last-command-event)))
      (insert closer))
     ;; Backslash-escaped: no pairing, no skipping.
     ((save-excursion
        (goto-char (1- (point)))
        (not (zerop (% (skip-syntax-backward "\\") 2))))
      nil)
     ;; Skip self.
     ((and (memq syntax '(?\) ?\" ?\$))
           electric-pair-skip-self
           (looking-at (concat "\\s-*"
                               (regexp-quote
                                (make-string 1 last-command-event))))
           ;; (eq (char-after) last-command-event)
           )
      ;; This is too late: rather than insert&delete we'd want to only skip (or
      ;; insert in overwrite mode).  The difference is in what goes in the
      ;; undo-log and in the intermediate state which might be visible to other
      ;; post-self-insert-hook.  We'll just have to live with it for now.
      ;; (delete-char 1)
      (replace-match "")
      )
     ;; Insert matching pair.
     ((not (or (not (memq syntax `(?\( ?\" ?\$)))
               overwrite-mode
               ;; I find it more often preferable not to pair when the
               ;; same char is next.
               (eq last-command-event (char-after))
               (eq last-command-event (char-before (1- (point))))
               ;; I also find it often preferable not to pair next to a word.
               (eq (char-syntax (following-char)) ?w)))
      (save-excursion (insert closer))))))