From 88248111d11bdcdf167112b9fb9a39026c45e5a3 Mon Sep 17 00:00:00 2001
From: Bozhidar Batsov <bozhidar@tradeo.com>
Date: Sat, 13 Jul 2013 14:15:16 +0300
Subject: [PATCH] Add prelude-duplicate-and-comment-current-line-or-region
 (fixes #348)

---
 README.md            |  1 +
 core/prelude-core.el | 24 ++++++++++++++++++++++++
 core/prelude-mode.el |  1 +
 3 files changed, 26 insertions(+)

diff --git a/README.md b/README.md
index 85488dc..1accf0f 100644
--- a/README.md
+++ b/README.md
@@ -227,6 +227,7 @@ Keybinding         | Description
 <kbd>C-c e</kbd> | Eval a bit of Emacs Lisp code and replace it with its result.
 <kbd>C-c s</kbd> | Swap two active windows.
 <kbd>C-c d</kbd> | Duplicate the current line (or region).
+<kbd>C-c M-d</kbd> | Duplicate and comment the current line (or region).
 <kbd>C-c r</kbd> | Rename the currently visited file and buffer.
 <kbd>C-c t</kbd> | Open a terminal emulator (`ansi-term`).
 <kbd>C-c k</kbd> | Kill all open buffers except the one you're currently in.
diff --git a/core/prelude-core.el b/core/prelude-core.el
index b2402b3..6aed171 100644
--- a/core/prelude-core.el
+++ b/core/prelude-core.el
@@ -222,6 +222,30 @@ there's a region, all lines that region covers will be duplicated."
                   (setq end (point))))
       (goto-char (+ origin (* (length region) arg) arg)))))
 
+;; TODO: Remove code duplication by extracting something more generic
+(defun prelude-duplicate-and-comment-current-line-or-region (arg)
+  "Duplicates and comments the current line or region ARG times.
+If there's no region, the current line will be duplicated.  However, if
+there's a region, all lines that region covers will be duplicated."
+  (interactive "p")
+  (let (beg end (origin (point)))
+    (if (and mark-active (> (point) (mark)))
+        (exchange-point-and-mark))
+    (setq beg (line-beginning-position))
+    (if mark-active
+        (exchange-point-and-mark))
+    (setq end (line-end-position))
+    (let ((region (buffer-substring-no-properties beg end)))
+      (comment-or-uncomment-region beg end)
+      (setq end (line-end-position))
+      (-dotimes arg
+                (lambda (n)
+                  (goto-char end)
+                  (newline)
+                  (insert region)
+                  (setq end (point))))
+      (goto-char (+ origin (* (length region) arg) arg)))))
+
 (defun prelude-rename-file-and-buffer ()
   "Renames current buffer and file it is visiting."
   (interactive)
diff --git a/core/prelude-mode.el b/core/prelude-mode.el
index 7c64762..70cd31f 100644
--- a/core/prelude-mode.el
+++ b/core/prelude-mode.el
@@ -54,6 +54,7 @@
     (define-key map (kbd "C-c s") 'prelude-swap-windows)
     (define-key map (kbd "C-c D") 'prelude-delete-file-and-buffer)
     (define-key map (kbd "C-c d") 'prelude-duplicate-current-line-or-region)
+    (define-key map (kbd "C-c M-d") 'prelude-duplicate-and-comment-current-line-or-region)
     (define-key map (kbd "C-c r") 'prelude-rename-file-and-buffer)
     (define-key map (kbd "C-c t") 'prelude-visit-term-buffer)
     (define-key map (kbd "C-c k") 'prelude-kill-other-buffers)