Emacs: Change Brackets 🚀

Here's command to change brackets in text.

For example, here's what you have:

matrix =
 [
   [3, 99, 'a'],
   [2, 77, 'a']
 ];

You want:

matrix =
 {
   {3, 99, 'a'},
   {2, 77, 'a'}
 };

Bracket change is useful when converting data from different languages or formats.

More examples:

• markdown format: `name`
• emacs format: `name'
• org format: ~name~
• org format: =name=
• common template [[name]]
• curly quote: “name”
• python list: [1,2,3]
• Wolfram Language list: {1,2,3}
• lisp list: (list 1 2 3)

put this in your Emacs Init File:

(defun xah-change-bracket-pairs (FromChars ToChars)
  "Change bracket pairs to another type or none.
For example, change all parenthesis () to square brackets [].
Works on current block or selection.

In lisp code, FromChars is a string with at least 2 spaces.
e.g.
paren ( )
french angle ‹ ›
double bracket [[ ]]
etc.
It is split by space, and last 2 items are taken as left and right brackets.

ToChars is similar, with a special value of
none
followed by 2 spaces.
,it means replace by empty string.

URL `http://xahlee.info/emacs/emacs/elisp_change_brackets.html'
Version: 2020-11-01 2023-03-31 2023-08-25 2023-09-29"
  (interactive
   (let ((xbrackets
          '(
            "square [ ]"
            "brace { }"
            "paren ( )"
            "greater < >"
            "double quote \" \""
            "single quote ' '"
            "emacs ` '"
            "markdown grave accent ` `"
            "double square [[ ]]"
            "tilde ~ ~"
            "equal = ="
            "curly double quote “ ”"
            "curly single quote ‘ ’"
            "french angle ‹ ›"
            "french double angle « »"
            "corner 「 」"
            "white corner 『 』"
            "lenticular 【 】"
            "white lenticular 〖 〗"
            "angle 〈 〉"
            "double angle 《 》"
            "tortoise 〔〕"
            "white tortoise 〘 〙"
            "white square 〚 〛"
            "white paren ⦅ ⦆"
            "white curly bracket ⦃ ⦄"
            "pointing angle 〈 〉"
            "angle with dot ⦑ ⦒"
            "curved angle ⧼ ⧽"
            "math square ⟦ ⟧"
            "math angle ⟨ ⟩"
            "math double angle ⟪ ⟫"
            "math flattened parenthesis ⟮ ⟯"
            "math white tortoise shell ⟬ ⟭"
            "heavy single quotation mark ornament ❛ ❜"
            "heavy double turned comma quotation mark ornament ❝ ❞"
            "medium parenthesis ornament ❨ ❩"
            "medium flattened parenthesis ornament ❪ ❫"
            "medium curly ornament ❴ ❵"
            "medium pointing angle ornament ❬ ❭"
            "heavy pointing angle quotation mark ornament ❮ ❯"
            "heavy pointing angle ornament ❰ ❱"
            "none  "
            )))
     (let ((completion-ignore-case t))
       (list
        (completing-read "Replace this:" xbrackets nil t nil nil (car xbrackets))
        (completing-read "To:" xbrackets nil t nil nil (car (last xbrackets)))))))
  (let (xp1 xp2 xleft xright xtoL xtoR)
    (let ((xbds (xah-get-bounds-of-block-or-region))) (setq xp1 (car xbds) xp2 (cdr xbds)))
    (let ((xsFrom (last (split-string FromChars " ") 2))
          (xsTo (last (split-string ToChars " ") 2)))

      ;; (when (< (length xsFrom) 3)
      ;; (error "cannot find input brackets %s" xsFrom))

      ;; (when (< (length xsTo) 3)
      ;;   (message "replace blacket is empty string")
      ;;   (setq xsTo (list "" "" "")))

      (setq xleft (car xsFrom)  xright (car (cdr xsFrom))
            xtoL (car xsTo) xtoR (car (cdr xsTo)))

      (save-excursion
        (save-restriction
          (narrow-to-region xp1 xp2)
          (let ((case-fold-search nil))
            (if (string-equal xleft xright)
                (let ((xx (regexp-quote xleft)))
                  (goto-char (point-min))
                  (while
                      (re-search-forward
                       (format "%s\\([^%s]+?\\)%s" xx xx xx)
                       nil t)
                    (overlay-put (make-overlay (match-beginning 0) (match-end 0)) 'face 'highlight)
                    (replace-match (concat xtoL "\\1" xtoR) t)))
              (progn
                (progn
                  (goto-char (point-min))
                  (while (search-forward xleft nil t)
                    (overlay-put (make-overlay (match-beginning 0) (match-end 0)) 'face 'highlight)
                    (replace-match xtoL t t)))
                (progn
                  (goto-char (point-min))
                  (while (search-forward xright nil t)
                    (overlay-put (make-overlay (match-beginning 0) (match-end 0)) 'face 'highlight)
                    (replace-match xtoR t t)))))))))))

requires package Emacs: xah-get-thing.el 📦