* lisp/sort.el (delete-duplicate-lines): Accept an optional `keep-blanks'

argument (before the `interactive' argument).

diff --git a/etc/NEWS b/etc/NEWS
index 42ad20669920733f06cc45b5df77ee907c8398cc..2fe3ba79d4f22ce3852c604b810b0866ee1201d7 100644 (file)
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -264,10 +264,12 @@ New features include:
   name and arguments.  Useful to trace the value of (current-buffer) or
   (point) when the function is invoked.
 
-** New command `delete-duplicate-lines' has two types of operation:
-when its arg ADJACENT is non-nil (when called interactively with C-u C-u)
+** New command `delete-duplicate-lines' has new types of operation:
+When its arg ADJACENT is non-nil (when called interactively with C-u C-u)
 it works like the utility `uniq'.  Otherwise by default it deletes
 duplicate lines everywhere in the region without regard to adjacency.
+When it arg KEEP-BLANKS is non-nil (when called interactively with C-u C-u C-u),
+duplicate blank lines are preserved.
 
 ** New `cycle-spacing' command allows cycling between having just one
 space, no spaces, or reverting to the original spacing.  Like

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 312bea5842ed9384648ac7f222e9fa76fefa78ac..242098b94b9c8e857fc7d003b29a91d973efa457 100644 (file)
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,8 @@
+2013-05-24  Sam Steingold  <sds@gnu.org>
+
+       * sort.el (delete-duplicate-lines): Accept an optional `keep-blanks'
+       argument (before the `interactive' argument).
+
 2013-05-24  Stefan Monnier  <monnier@iro.umontreal.ca>
 
        * image-mode.el (image-mode-winprops): Add winprops to

diff --git a/lisp/sort.el b/lisp/sort.el
index 56e97061d1325a3e4537259622718dacf57af84e..9493768f6a0254a087405f1e5f68ed940c0ea443 100644 (file)
--- a/lisp/sort.el
+++ b/lisp/sort.el
@@ -568,7 +568,8 @@ From a program takes two point or marker arguments, BEG and END."
       (insert (car ll)))))
 
 ;;;###autoload
-(defun delete-duplicate-lines (beg end &optional reverse adjacent interactive)
+(defun delete-duplicate-lines (beg end &optional reverse adjacent keep-blanks
+                               interactive)
   "Delete duplicate lines in the region between BEG and END.
 
 If REVERSE is nil, search and delete duplicates forward keeping the first
@@ -582,6 +583,9 @@ delete repeated lines only if they are adjacent.  It works like the utility
 this is more efficient in performance and memory usage than when ADJACENT
 is nil that uses additional memory to remember previous lines.
 
+If KEEP-BLANKS is non-nil (when called interactively with three C-u prefixes),
+duplicate blank lines are preserved.
+
 When called from Lisp and INTERACTIVE is omitted or nil, return the number
 of deleted duplicate lines, do not print it; if INTERACTIVE is t, the
 function behaves in all respects as if it had been called interactively."
@@ -591,6 +595,7 @@ function behaves in all respects as if it had been called interactively."
      (list (region-beginning) (region-end)
           (equal current-prefix-arg '(4))
           (equal current-prefix-arg '(16))
+          (equal current-prefix-arg '(64))
           t)))
   (let ((lines (unless adjacent (make-hash-table :weakness 'key :test 'equal)))
        line prev-line
@@ -605,14 +610,16 @@ function behaves in all respects as if it had been called interactively."
               (and (< (point) end) (not (eobp))))
        (setq line (buffer-substring-no-properties
                    (line-beginning-position) (line-end-position)))
-       (if (if adjacent (equal line prev-line) (gethash line lines))
-           (progn
-             (delete-region (progn (forward-line 0) (point))
-                            (progn (forward-line 1) (point)))
-             (if reverse (forward-line -1))
-             (setq count (1+ count)))
-         (if adjacent (setq prev-line line) (puthash line t lines))
-         (forward-line (if reverse -1 1)))))
+        (if (and keep-blanks (string= "" line))
+            (forward-line 1)
+          (if (if adjacent (equal line prev-line) (gethash line lines))
+              (progn
+                (delete-region (progn (forward-line 0) (point))
+                               (progn (forward-line 1) (point)))
+                (if reverse (forward-line -1))
+                (setq count (1+ count)))
+            (if adjacent (setq prev-line line) (puthash line t lines))
+            (forward-line (if reverse -1 1))))))
     (set-marker beg nil)
     (set-marker end nil)
     (when interactive