X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/e61d39cddfd015032a6419ce75c36ecdf1e9fe9f..a8e1414c0d66903884059361ecc8ec70da37cf35:/lisp/sort.el

diff --git a/lisp/sort.el b/lisp/sort.el
index 44f90fff37..8bc71388ad 100644
--- a/lisp/sort.el
+++ b/lisp/sort.el
@@ -1,10 +1,10 @@
 ;;; sort.el --- commands to sort text in an Emacs buffer
 
-;; Copyright (C) 1986-1987, 1994-1995, 2001-2012
-;;   Free Software Foundation, Inc.
+;; Copyright (C) 1986-1987, 1994-1995, 2001-2016 Free Software
+;; Foundation, Inc.
 
 ;; Author: Howie Kaye
-;; Maintainer: FSF
+;; Maintainer: emacs-devel@gnu.org
 ;; Keywords: unix
 
 ;; This file is part of GNU Emacs.
@@ -77,8 +77,13 @@ ENDKEYFUN moves from the start of the sort key to the end of the sort key.
 ENDKEYFUN may be nil if STARTKEYFUN returns a value or if it would be the
 same as ENDRECFUN.
 
-PREDICATE is the function to use to compare keys.  If keys are numbers,
-it defaults to `<', otherwise it defaults to `string<'."
+PREDICATE, if non-nil, is the predicate function for comparing
+keys; it is called with two arguments, the keys to compare, and
+should return non-nil if the first key should sort before the
+second key.  If PREDICATE is nil, comparison is done with `<' if
+the keys are numbers, with `compare-buffer-substrings' if the
+keys are cons cells (the car and cdr of each cons cell are taken
+as start and end positions), and with `string<' otherwise."
   ;; Heuristically try to avoid messages if sorting a small amt of text.
   (let ((messages (> (- (point-max) (point-min)) 50000)))
     (save-excursion
@@ -311,7 +316,7 @@ FIELD, BEG and END.  BEG and END specify region to sort."
 ;;			       (point)
 ;;			       (save-excursion
 ;;				 (re-search-forward
-;;				  "[+-]?[0-9]*\.?[0-9]*\\([eE][+-]?[0-9]+\\)?")
+;;				  "[+-]?[0-9]*\\.?[0-9]*\\([eE][+-]?[0-9]+\\)?")
 ;;				 (point))))))
 ;;		 nil))
 
@@ -562,6 +567,68 @@ From a program takes two point or marker arguments, BEG and END."
 	(setq ll (cdr ll)))
       (insert (car ll)))))
 
+;;;###autoload
+(defun delete-duplicate-lines (beg end &optional reverse adjacent keep-blanks
+                               interactive)
+  "Delete all but one copy of any identical lines in the region.
+Non-interactively, arguments BEG and END delimit the region.
+Normally it searches forwards, keeping the first instance of
+each identical line.  If REVERSE is non-nil (interactively, with
+a C-u prefix), it searches backwards and keeps the last instance of
+each repeated line.
+
+Identical lines need not be adjacent, unless the argument
+ADJACENT is non-nil (interactively, with a C-u C-u prefix).
+This is a more efficient mode of operation, and may be useful
+on large regions that have already been sorted.
+
+If the argument KEEP-BLANKS is non-nil (interactively, with a
+C-u C-u C-u prefix), it retains repeated blank lines.
+
+Returns the number of deleted lines.  Interactively, or if INTERACTIVE
+is non-nil, it also prints a message describing the number of deletions."
+  (interactive
+   (progn
+     (barf-if-buffer-read-only)
+     (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 :test 'equal)))
+	line prev-line first-line
+	(count 0)
+	(beg (copy-marker beg))
+	(end (copy-marker end)))
+    (save-excursion
+      (goto-char (if reverse end beg))
+      (if (and reverse (bolp)) (forward-char -1))
+      (while (if reverse
+		 (not first-line)
+	       (and (< (point) end) (not (eobp))))
+	(setq first-line (and reverse (or (<= (point) beg) (bobp))))
+	(setq line (buffer-substring-no-properties
+		    (line-beginning-position) (line-end-position)))
+        (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
+      (message "Deleted %d %sduplicate line%s%s"
+	       count
+	       (if adjacent "adjacent " "")
+	       (if (= count 1) "" "s")
+	       (if reverse " backward" "")))
+    count))
+
 (provide 'sort)
 
 ;;; sort.el ends here