change-case.el

;; FIXME work in progress

;; ----------------------------------------------------------------------
;; Gets a cons cell indicating the bounds of the current region (if set) or word
(defun bounds-of-word-or-region ()
  (if (and transient-mark-mode mark-active)
      (cons (region-beginning) (region-end))
    (bounds-of-thing-at-point 'symbol)))

;; ----------------------------------------------------------------------
(defun camelcase-region (start end &optional upcase)
  "Changes region from snake_case to camelCase (or CamelCase is upcase is t)"
  (interactive "r")
  (save-excursion
    (when upcase
      (goto-char start)
      (while (re-search-forward "\\([^[:alnum:]_]\\)\\([[:lower:]]\\)" nil t)
	(replace-match (concat (match-string 1) (upcase (match-string 2))))))
    (goto-char start)
    (while (re-search-forward "_\\(.\\)" end t)
      (replace-match (upcase (match-string 1)))
      (setq end (1- end)))))

;; ----------------------------------------------------------------------
;; Convert region (if set) or word at point to camel-case
(defun camelcase-word-or-region  (&optional upcase)
  "Changes word or region from snake_case to camelCase (or CamelCase if upcase is t)"
  (interactive "P")
  (let ((bounds (bounds-of-word-or-region)))
    (camelcase-region (car bounds) (cdr bounds) upcase)))

;; ----------------------------------------------------------------------
;; snakecase-region
(defun snakecase-region (start end &optional upcase)
  "Changes region from camelCase to snake_case (or SNAKE_CASE if upcase is t)"
  (interactive "rP")
  (save-excursion
    (let ((case-fold-search nil)
	  (last-case t))
      (when upcase
	; uppercase word endings
	(goto-char start)
	(while (re-search-forward "\\([[:lower:][:digit:]_]+\\)\\([^[::]_]\\)" nil t)
	  (replace-match (concat (upcase (match-string 1)) (match-string 2)))))
      ; insert underscores between lower->uppercase transitions
      (goto-char start)
      (while (re-search-forward "\\([^[:upper:]]+\\)\\([[:upper:]]\\)" end t)
	(replace-match (if upcase
			   (upcase (concat (match-string 1) "_" (match-string 2)))
			   (downcase (concat (match-string 1) "_" (match-string 2)))))
	(setq end (1+ end))))))
	
;; ----------------------------------------------------------------------
(defun snakecase-word-or-region (&optional upcase)
  "Changes word or region from camelCase to snake_case (or SNAKE_CASE if upcase is t)"
  (interactive "P")
  (let ((bounds (bounds-of-word-or-region)))
   
;;; Suggested key bindings
;;; (global-set-key (kbd "C-c C--") 'camelcase-word-or-region)
;;; (global-set-key (kbd "C-c C-_") 'snakecase-word-or-region)