initial commit

README.org

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+* multiple-cursors.el
+
+An experiment in multiple cursors for emacs. Still very much in beta.

multiple-cursors.el

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+(defface mc/cursor-face
+  '((t (:inverse-video t)))
+  "The face used for additional cursors"
+  :group 'multiple-cursors)
+
+(defun mc/make-cursor-overlay-at-eol (pos)
+  (let ((overlay (make-overlay pos pos nil nil t)))
+    (overlay-put overlay 'after-string (propertize " " 'face 'mc/cursor-face))
+    overlay))
+
+(defun mc/make-cursor-overlay-inline (pos)
+  (let ((overlay (make-overlay pos (1+ pos) nil nil t)))
+    (overlay-put overlay 'face 'mc/cursor-face)
+    overlay))
+
+(defun mc/make-cursor-overlay-at-point ()
+  (if (eolp)
+      (mc/make-cursor-overlay-at-eol (point))
+    (mc/make-cursor-overlay-inline (point))))
+
+(defun mc/add-cursor-at-point ()
+  (let ((overlay (mc/make-cursor-overlay-at-point)))
+    (overlay-put overlay 'type 'additional-cursor)
+    (overlay-put overlay 'priority 100)))
+
+(setq mc--cmds '(self-insert-command
+                 previous-line
+                 next-line
+                 newline
+                 right-char
+                 right-word
+                 left-char
+                 left-word
+                 yank
+                 kill-word
+                 kill-region-or-backward-word
+                 backward-kill-word
+                 backward-delete-char-untabify
+                 delete-char
+                 delete-backward-char
+                 move-end-of-line-or-next-line
+                 move-start-of-line-or-prev-line))
+
+(defun mc/execute-this-command-for-all-cursors ()
+  (if (not (memq this-original-command mc--cmds))
+      (message "Skipping %S" this-original-command)
+    (save-excursion
+      (mapc #'(lambda (o)
+                (when (eq (overlay-get o 'type) 'additional-cursor)
+                  (goto-char (overlay-start o))
+                  (delete-overlay o)
+                  (ignore-errors
+                    (call-interactively this-original-command)
+                    (mc/add-cursor-at-point))))
+            (overlays-in (point-min) (point-max))))))
+
+(defun mc/remove-additional-cursors ()
+  (mapc #'(lambda (o)
+            (when (eq (overlay-get o 'type) 'additional-cursor)
+              (delete-overlay o)))
+        (overlays-in (point-min) (point-max))))
+
+(defvar mc/keymap nil
+  "Keymap while multiple cursors are active.")
+(if mc/keymap
+    nil
+  (setq mc/keymap (make-sparse-keymap))
+  (define-key mc/keymap (kbd "C-g") 'multiple-cursors-mode))
+
+(define-minor-mode multiple-cursors-mode
+  "Mode while multiple cursors are active."
+  nil " mc" mc/keymap
+  (cond ((not multiple-cursors-mode)
+         (remove-hook 'post-command-hook 'mc/execute-this-command-for-all-cursors t)
+         (mc/remove-additional-cursors))
+        (t (add-hook 'post-command-hook 'mc/execute-this-command-for-all-cursors t t))))
+
+(defun mc/edit-ends-of-lines ()
+  (interactive)
+  (mc/remove-additional-cursors)
+  (let* ((point-line (line-number-at-pos))
+         (mark-line (save-excursion (exchange-point-and-mark) (line-number-at-pos)))
+         (num-cursors (abs (- point-line mark-line)))
+         (navigation-func (if (< point-line mark-line) 'previous-line 'next-line)))
+    (exchange-point-and-mark)
+    (while (not (eq (line-number-at-pos) point-line))
+      (end-of-line)
+      (mc/add-cursor-at-point)
+      (funcall navigation-func))
+    (end-of-line)
+    (deactivate-mark)
+    (multiple-cursors-mode)))
+
+(provide 'multiple-cursors)