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emacs lisp defuns to change the case (camelCase <-> snake_case) of the word under cursor, or an entire region if selected. NOTE: the snake-case defuns do not work, they just camelCase. Ooops.
;; Grateful thanks are given to Brian Marick (@marick) for helping me
;; write these. I got the original idea while reading through
;; http://xahlee.org/emacs/elisp_idioms.html, but couldn't work out
;; the elisp regexes. Brian Marick (@marick) stepped in and helped. He
;; took my tortured and broken camelcase-region and turned it into
;; something that actually worked. I then created
;; camelcase-word-or-region. I then wrote the snakecase versions but I
;; see now that all I did was copy the camelcase defuns over and,
;; meaning to go back and finish them Real Soon Now, forgot all about
;; them. I've had a quick look (2011-02-27) but elisp regexes are
;; still pretty slippery to me, so I have decided to err on the side
;; of "Showing This To Jim Weirich" (beacuse he expressed interest in
;; the camelcase defun) and have just marked the offending code and
;; left it unfixed.
;;
;; Help me, Obi-Wan Weirichobi, you're my only hope!
;; ----------------------------------------------------------------------
;; camelcase-region Given a region of text in snake_case format,
;; changes it to camelCase.
(defun camelcase-region (start end)
"Changes region from snake_case to camelCase"
(interactive "r")
(save-restriction (narrow-to-region start end)
(goto-char (point-min))
(while (re-search-forward "_\\(.\\)" nil t)
(replace-match (upcase (match-string 1))))))
;; ----------------------------------------------------------------------
;; cadged largely from http://xahlee.org/emacs/elisp_idioms.html:
;;
(defun camelcase-word-or-region ()
"Changes word or region from snake_case to camelCase"
(interactive)
(let (pos1 pos2 bds)
(if (and transient-mark-mode mark-active)
(setq pos1 (region-beginning) pos2 (region-end))
(progn
(setq bds (bounds-of-thing-at-point 'symbol))
(setq pos1 (car bds) pos2 (cdr bds))))
(camelcase-region pos1 pos2)))
;; ----------------------------------------------------------------------
;; snakecase-region
;; Given a region of text in camelCase format, changes it to snake_case.
;;
;; BUG: This is actually just a repeat of camelcase-region!
(defun snakecase-region (start end)
"Changes region from camelCase to snake_case"
(interactive "r")
(save-restriction (narrow-to-region start end)
(goto-char (point-min))
(while (re-search-forward "_\\(.\\)" nil t)
(replace-match (upcase (match-string 1))))))
;; ----------------------------------------------------------------------
;; Given a region of text in camelCase format, changes it to snake_case.
(defun snakecase-word-or-region ()
"Changes word or region from camelCase to snake_case"
(interactive)
(let (pos1 pos2 bds)
(if (and transient-mark-mode mark-active)
(setq pos1 (region-beginning) pos2 (region-end))
(progn
(setq bds (bounds-of-thing-at-point 'symbol))
(setq pos1 (car bds) pos2 (cdr bds))))
(snakecase-region pos1 pos2)))
(global-set-key (kbd "C-c C--") 'camelcase-word-or-region)
(global-set-key (kbd "C-c C-_") 'snakecase-word-or-region)
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