- (setq dired-actual-switches
- (let (case-fold-search)
- (if (string-match " " dired-actual-switches)
- ;; New toggle scheme: add/remove a trailing " -t"
- (if (string-match " -t\\'" dired-actual-switches)
- (substring dired-actual-switches 0 (match-beginning 0))
- (concat dired-actual-switches " -t"))
- ;; old toggle scheme: look for some 't' switch and add/remove it
- (concat
- "-l"
- (dired-replace-in-string (concat "[-lt"
- dired-ls-sorting-switches "]")
- ""
- dired-actual-switches)
- (if (string-match (concat "[t" dired-ls-sorting-switches "]")
- dired-actual-switches)
- ""
- "t")))))
+ (let ((sorting-by-date (string-match dired-sort-by-date-regexp
+ dired-actual-switches))
+ ;; Regexp for finding (possibly embedded) -t switches.
+ (switch-regexp "\\(\\`\\| \\)-\\([a-su-zA-Z]*\\)\\(t\\)\\([^ ]*\\)")
+ case-fold-search)
+ ;; Remove the -t switch.
+ (while (string-match switch-regexp dired-actual-switches)
+ (if (and (equal (match-string 2 dired-actual-switches) "")
+ (equal (match-string 4 dired-actual-switches) ""))
+ ;; Remove a stand-alone -t switch.
+ (setq dired-actual-switches
+ (replace-match "" t t dired-actual-switches))
+ ;; Remove a switch of the form -XtY for some X and Y.
+ (setq dired-actual-switches
+ (replace-match "" t t dired-actual-switches 3))))
+ ;; Now, if we weren't sorting by date before, add the -t switch.
+ (unless sorting-by-date
+ (setq dired-actual-switches (concat dired-actual-switches " -t"))))