Emacs: Insert Brackets by Pair 🚀

By Xah Lee. Date: . Last updated: .

This page shows a command xah-insert-bracket-pair to insert bracket pair, better than the emacs builtin electric-pair-mode .

Emacs has electric-pair-mode. It inserts a bracket pair when you type the left bracket. [see Emacs: Insert Bracket Pairs, electric-pair-mode]

Problems of electric-pair-mode

Advantages of xah-insert-bracket-pair

Bracket Pair Insertion Commands

Put this in your Emacs Init File:

(defun xah-insert-bracket-pair (LBracket RBracket &optional WrapMethod)
  "Insert brackets around selection, word, at point, and maybe move cursor in between.

 LBracket and RBracket are strings. WrapMethod must be either `line' or `block'. `block' means between empty lines.

• if there is a region, add brackets around region.
• If WrapMethod is `line', wrap around line.
• If WrapMethod is `block', wrap around block.
• if cursor is at beginning of line and its not empty line and contain at least 1 space, wrap around the line.
• If cursor is at end of a word or buffer, one of the following will happen:
 xyz▮ → xyz(▮)
 xyz▮ → (xyz▮)       if in one of the lisp modes.
• wrap brackets around word if any. e.g. xy▮z → (xyz▮). Or just (▮)

URL `http://xahlee.info/emacs/emacs/elisp_insert_brackets_by_pair.html'
Version: 2017-01-17 2021-08-12"
  (if (region-active-p)
      (progn
        (let ( ($p1 (region-beginning)) ($p2 (region-end)))
          (goto-char $p2) (insert RBracket)
          (goto-char $p1) (insert LBracket)
          (goto-char (+ $p2 2))))
    (let ($p1 $p2)
      (cond
       ((eq WrapMethod 'line)
        (setq $p1 (line-beginning-position) $p2 (line-end-position))
        (goto-char $p2)
        (insert RBracket)
        (goto-char $p1)
        (insert LBracket)
        (goto-char (+ $p2 (length LBracket))))
       ((eq WrapMethod 'block)
        (save-excursion
          (let (($bds (xah-get-bounds-of-block-or-region))) (setq $p1 (car $bds) $p2 (cdr $bds)))
          (goto-char $p2)
          (insert RBracket)
          (goto-char $p1)
          (insert LBracket)
          (goto-char (+ $p2 (length LBracket)))))
       ( ;  do line. line must contain space
        (and
         (eq (point) (line-beginning-position))
         ;; (string-match " " (buffer-substring-no-properties (line-beginning-position) (line-end-position)))
         (not (eq (line-beginning-position) (line-end-position))))
        (insert LBracket )
        (end-of-line)
        (insert  RBracket))
       ((and
         (or ; cursor is at end of word or buffer. i.e. xyz▮
          (looking-at "[^-_[:alnum:]]")
          (eq (point) (point-max)))
         (not (or
               (string-equal major-mode "xah-elisp-mode")
               (string-equal major-mode "emacs-lisp-mode")
               (string-equal major-mode "lisp-mode")
               (string-equal major-mode "lisp-interaction-mode")
               (string-equal major-mode "common-lisp-mode")
               (string-equal major-mode "clojure-mode")
               (string-equal major-mode "xah-clojure-mode")
               (string-equal major-mode "scheme-mode"))))
        (progn
          (setq $p1 (point) $p2 (point))
          (insert LBracket RBracket)
          (search-backward RBracket )))
       (t (progn
            ;; wrap around “word”. basically, want all alphanumeric, plus hyphen and underscore, but don't want space or punctuations. Also want chinese chars
            ;; 我有一帘幽梦，不知与谁能共。多少秘密在其中，欲诉无人能懂。
            (skip-chars-backward "-_[:alnum:]")
            (setq $p1 (point))
            (skip-chars-forward "-_[:alnum:]")
            (setq $p2 (point))
            (goto-char $p2)
            (insert RBracket)
            (goto-char $p1)
            (insert LBracket)
            (goto-char (+ $p2 (length LBracket)))))))))

require: Emacs: xah-get-thing.el

Now we define the commands:

(defun xah-insert-paren () (interactive) (xah-insert-bracket-pair "(" ")") )
(defun xah-insert-square-bracket () (interactive) (xah-insert-bracket-pair "[" "]") )
(defun xah-insert-brace () (interactive) (xah-insert-bracket-pair "{" "}") )

(defun xah-insert-markdown-quote () (interactive) (xah-insert-bracket-pair "`" "`") )
(defun xah-insert-markdown-triple-quote () (interactive) (xah-insert-bracket-pair "```\n" "\n```"))

(defun xah-insert-double-curly-quote () (interactive) (xah-insert-bracket-pair "“" "”") )
(defun xah-insert-curly-single-quote () (interactive) (xah-insert-bracket-pair "‘" "’") )
(defun xah-insert-single-angle-quote () (interactive) (xah-insert-bracket-pair "‹" "›") )
(defun xah-insert-double-angle-quote () (interactive) (xah-insert-bracket-pair "«" "»") )
(defun xah-insert-ascii-double-quote () (interactive) (xah-insert-bracket-pair "\"" "\"") )
(defun xah-insert-ascii-single-quote () (interactive) (xah-insert-bracket-pair "'" "'") )
(defun xah-insert-emacs-quote () (interactive) (xah-insert-bracket-pair "`" "'") )
(defun xah-insert-corner-bracket () (interactive) (xah-insert-bracket-pair "「" "」" ) )
(defun xah-insert-white-corner-bracket () (interactive) (xah-insert-bracket-pair "『" "』") )
(defun xah-insert-angle-bracket () (interactive) (xah-insert-bracket-pair "〈" "〉") )
(defun xah-insert-double-angle-bracket () (interactive) (xah-insert-bracket-pair "《" "》") )
(defun xah-insert-white-lenticular-bracket () (interactive) (xah-insert-bracket-pair "〖" "〗") )
(defun xah-insert-black-lenticular-bracket () (interactive) (xah-insert-bracket-pair "【" "】") )
(defun xah-insert-tortoise-shell-bracket () (interactive) (xah-insert-bracket-pair "〔" "〕" ) )

[see Unicode: Brackets, Quotes «»「」【】《》]

Setting Up Keys

Now you can set any key to call your commands.

(global-set-key (kbd "<f8> 7") 'xah-insert-brace) ; {}
(global-set-key (kbd "<f8> 8") 'xah-insert-paren) ; ()
(global-set-key (kbd "<f8> 9") 'xah-insert-bracket) ; []

or

(global-set-key (kbd "M-7") 'xah-insert-brace) ; {}
(global-set-key (kbd "M-8") 'xah-insert-paren) ; ()
(global-set-key (kbd "M-9") 'xah-insert-bracket) ; []

[see Emacs: How to Define Keybinding]

Emacs, Work with Brackets