From Francis J. Wright <F.J.Wright@maths.qmw.ac.uk>:

Better support for the Mac and MS-Windows.
(ls-lisp): New defgroup.
(ls-lisp-emulation, ls-lisp-ignore-case, ls-lisp-dirs-first)
(ls-lisp-verbosity, ls-lisp-use-insert-directory-program)
(ls-lisp-support-shell-wildcards): New defcustoms.
(ls-lisp-parse-symlink): New function.
(insert-directory): Code to convert switches to a list and set up
the wildcard argument copied from ls-lisp-insert-directory.
(ls-lisp-insert-directory): New argument TIME-INDEX.  Add support
for -C and -R switches.
(ls-lisp-column-format): New function.
(ls-lisp-delete-matching, ls-lisp-handle-switches)
(ls-lisp-format-time): Add doc strings.
(ls-lisp-handle-switches): Handle -U, -S, -X, and -F switches.
Support ls-lisp-dirs-first.
(ls-lisp-classify, ls-lisp-extension): New functions.
(ls-lisp-format): Optionally support emulation of symlinks.
Support -i, -s, and -G switches.

1 files changed, 443 insertions, 216 deletions

diff --git a/lisp/ls-lisp.el b/lisp/ls-lisp.el
index fa7b462b3ff..67b87c0be55 100644
--- a/lisp/ls-lisp.el
+++ b/lisp/ls-lisp.el
@@ -1,10 +1,11 @@
 ;;; ls-lisp.el --- emulate insert-directory completely in Emacs Lisp
 
-;; Copyright (C) 1992, 1994 Free Software Foundation, Inc.
+;; Copyright (C) 1992, 1994, 2000 Free Software Foundation, Inc.
 
-;; Author: Sebastian Kremer <sk@thp.uni-koeln.de>
-;; Maintainer: FSF
-;; Keywords: unix
+;; Author:		Sebastian Kremer <sk@thp.uni-koeln.de>
+;; Modified by:		Francis J. Wright <F.J.Wright@maths.qmw.ac.uk>
+;; Maintainer:		FSF
+;; Keywords:		unix, dired
 
 ;; This file is part of GNU Emacs.
 
@@ -25,55 +26,137 @@
 
 ;;; Commentary:
 
-;; INSTALLATION =======================================================
-;; 
-;; Put this file into your load-path.  To use it, load it
-;; with (load "ls-lisp").
+;; OVERVIEW ==========================================================
 
-;; OVERVIEW ===========================================================
+;; This file redefines the function `insert-directory' to implement it
+;; directly from Emacs lisp, without running ls in a subprocess.  It
+;; is useful if you cannot afford to fork Emacs on a real memory UNIX,
+;; under VMS or other non-UNIX platforms if you don't have the ls
+;; program, or if you want a different format from what ls offers.
 
-;; This file overloads the function insert-directory to implement it
-;; directly from Emacs lisp, without running `ls' in a subprocess.
+;; This function can use regexps instead of shell wildcards.  If you
+;; enter regexps remember to double each $ sign.  For example, to
+;; include files *.el, enter `.*\.el$$', resulting in the regexp
+;; `.*\.el$'.
 
-;; It is useful if you cannot afford to fork Emacs on a real memory UNIX,
-;; under VMS, or if you don't have the ls program, or if you want
-;; different format from what ls offers.
+;; RESTRICTIONS ======================================================
 
-;; This function uses regexps instead of shell
-;; wildcards.  If you enter regexps remember to double each $ sign.
-;; For example, to include files *.el, enter `.*\.el$$',
-;; resulting in the regexp `.*\.el$'.
+;; * A few obscure ls switches are still ignored: see the docstring of
+;; `insert-directory'.
 
-;;  RESTRICTIONS =====================================================
+;; * Generally only numeric uid/gid.
 
-;; * many ls switches are ignored, see docstring of `insert-directory'.
+;; TO DO =============================================================
 
-;; * Only numeric uid/gid
+;; Complete handling of F switch (if/when possible).
 
-;; TODO ==============================================================
+;; FJW: May be able to sort much faster by consing the sort key onto
+;; the front of each list element, sorting and then stripping the key
+;; off again!
 
-;; Recognize some more ls switches: R F
-
-;;; Code:
+;;; History:
 
-;;;###autoload
-(defvar ls-lisp-support-shell-wildcards t
-  "*Non-nil means file patterns are treated as shell wildcards.
-nil means they are treated as Emacs regexps (for backward compatibility).
-This variable is checked by \\[insert-directory] only when `ls-lisp.el'
-package is used.")
+;; Written originally by Sebastian Kremer <sk@thp.uni-koeln.de>
+;; Revised by Andrew Innes and Geoff Volker (and maybe others).
 
-(defvar ls-lisp-dired-ignore-case nil
-  "Non-nil causes dired buffers to sort alphabetically regardless of case.")
+;; Modified by Francis J. Wright <F.J.Wright@maths.qmw.ac.uk>, mainly
+;; to support many more ls options, "platform emulation", hooks for
+;; external symbolic link support and more robust sorting.
+
+;;; Code:
 
-(defvar ls-lisp-use-insert-directory-program nil
-  "Non-nil causes ls-lisp to revert back to using `insert-directory-program'.
+;;;###autoload
+(defgroup ls-lisp nil
+  "Emulate the ls program completely in Emacs Lisp."
+  :group 'dired)
+
+(defcustom ls-lisp-emulation
+  (cond ((eq system-type 'macos) 'MacOS)
+	;; ((eq system-type 'windows-nt) 'MS-Windows)
+	((memq system-type
+	       '(hpux dgux usg-unix-v unisoft-unix rtu irix berkeley-unix))
+	 'UNIX))			; very similar to GNU
+  ;; Anything else defaults to nil, meaning GNU.
+  "*Platform to emulate: GNU (default), MacOS, MS-Windows, UNIX.
+Corresponding value is one of the atoms: nil, MacOS, MS-Windows, UNIX.
+Sets default values for: `ls-lisp-ignore-case', `ls-lisp-dirs-first',
+`ls-lisp-verbosity'.  Need not match actual platform.  Changing this
+option will have no effect until you restart Emacs."
+  :type '(choice (const :tag "GNU" nil)
+		 (const MacOS)
+		 (const MS-Windows)
+		 (const UNIX))
+  :group 'ls-lisp)
+
+(defcustom ls-lisp-ignore-case
+  ;; Name change for consistency with other option names.
+  (or (memq ls-lisp-emulation '(MS-Windows MacOS))
+      (and (boundp 'ls-lisp-dired-ignore-case) ls-lisp-dired-ignore-case))
+  "*Non-nil causes ls-lisp alphabetic sorting to ignore case."
+  :type 'boolean
+  :group 'ls-lisp)
+
+(defcustom ls-lisp-dirs-first (eq ls-lisp-emulation 'MS-Windows)
+  "*Non-nil causes ls-lisp to sort directories first in any ordering.
+\(Or last if it is reversed.)  Follows Microsoft Windows Explorer."
+  ;; Functionality suggested by Chris McMahan <cmcmahan@one.net>
+  :type 'boolean
+  :group 'ls-lisp)
+
+(defcustom ls-lisp-verbosity
+  (cond ((eq ls-lisp-emulation 'MacOS) nil)
+	((eq ls-lisp-emulation 'MS-Windows)
+	 (if (and (fboundp 'w32-using-nt) (w32-using-nt))
+	     '(links)))			; distinguish NT/2K from 9x
+	((eq ls-lisp-emulation 'UNIX) '(links uid)) ; UNIX ls
+	(t '(links uid gid)))		; GNU ls
+  "*A list of optional file attributes that ls-lisp should display.
+It should contain none or more of the symbols: links, uid, gid.
+Nil (or an empty list) means display none of them.
+
+Concepts come from UNIX: `links' means count of names associated with
+the file\; `uid' means user (owner) identifier\; `gid' means group
+identifier.
+
+If emulation is MacOS then default is nil\;
+if emulation is MS-Windows then default is `(links)' if platform is
+Windows NT/2K, nil otherwise\;
+if emulation is UNIX then default is `(links uid)'\;
+if emulation is GNU then default is `(links uid gid)'."
+  ;; Functionality suggested by Howard Melman <howard@silverstream.com>
+  :type '(set (const :tag "Show Link Count" links)
+	      (const :tag "Show User" uid)
+	      (const :tag "Show Group" gid))
+  :group 'ls-lisp)
+
+(defcustom ls-lisp-use-insert-directory-program nil
+  "*Non-nil causes ls-lisp to revert back to using `insert-directory-program'.
 This is useful on platforms where ls-lisp is dumped into Emacs, such as
 Microsoft Windows, but you would still like to use a program to list
-the contents of a directory.")
+the contents of a directory."
+  :type 'boolean
+  :group 'ls-lisp)
+
+(defcustom ls-lisp-support-shell-wildcards t
+  "*Non-nil means ls-lisp treats file patterns as shell wildcards.
+Otherwise they are treated as Emacs regexps (for backward compatibility)."
+  :type 'boolean
+  :group 'ls-lisp)
+
+;; Remember the original insert-directory function
+(or (featurep 'ls-lisp)  ; FJW: unless this file is being reloaded!
+    (fset 'original-insert-directory (symbol-function 'insert-directory)))
+
+;; This stub is to allow ls-lisp to parse symbolic links via another
+;; library such as w32-symlinks.el from
+;; http://centaur.qmw.ac.uk/Emacs/:
+(defun ls-lisp-parse-symlink (file-name)
+  "This stub may be redefined to parse FILE-NAME as a symlink.
+It should return nil or the link target as a string."
+  nil)
 
-;; Remember the original insert-directory function.
-(fset 'original-insert-directory (symbol-function 'insert-directory))
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 (defun insert-directory (file switches &optional wildcard full-directory-p)
   "Insert directory listing for FILE, formatted according to SWITCHES.
@@ -83,216 +166,360 @@ Optional third arg WILDCARD means treat FILE as shell wildcard.
 Optional fourth arg FULL-DIRECTORY-P means file is a directory and
 switches do not contain `d', so that a full listing is expected.
 
-This version of the function comes from `ls-lisp.el'.  Depending upon
-the value of `ls-lisp-use-insert-directory-program', it will use an
-external program if non-nil or the lisp function `ls-lisp-insert-directory'
-otherwise."
+This version of the function comes from `ls-lisp.el'.
+If the value of `ls-lisp-use-insert-directory-program' is non-nil then
+it works exactly like the version from `files.el' and runs a directory
+listing program whose name is in the variable
+`insert-directory-program'; if also WILDCARD is non-nil then it runs
+the shell specified by `shell-file-name'.  If the value of
+`ls-lisp-use-insert-directory-program' is nil then it runs a Lisp
+emulation.
+
+The Lisp emulation does not run any external programs or shells.  It
+supports ordinary shell wildcards if `ls-lisp-support-shell-wildcards'
+is non-nil; otherwise, it interprets wildcards as regular expressions
+to match file names.  It does not support all `ls' switches -- those
+that work are: A a c i r S s t u U X g G B C R and F partly."
   (if ls-lisp-use-insert-directory-program
       (original-insert-directory file switches wildcard full-directory-p)
-    (ls-lisp-insert-directory file switches wildcard full-directory-p)))
-
-(defun ls-lisp-insert-directory (file switches &optional wildcard full-directory-p)
+    ;; We need the directory in order to find the right handler.
+    (let ((handler (find-file-name-handler (expand-file-name file)
+					   'insert-directory)))
+      (if handler
+	  (funcall handler 'insert-directory file switches
+		   wildcard full-directory-p)
+	;; Convert SWITCHES to a list of characters.
+	(setq switches (delete ?- (append switches nil)))
+	(if wildcard
+	    (setq wildcard
+		  (if ls-lisp-support-shell-wildcards
+		      (wildcard-to-regexp (file-name-nondirectory file))
+		    (file-name-nondirectory file))
+		  file (file-name-directory file))
+	  (if (memq ?B switches) (setq wildcard "[^~]\\'")))
+	(ls-lisp-insert-directory
+	 file switches (ls-lisp-time-index switches)
+	 wildcard full-directory-p)))))
+
+(defun ls-lisp-insert-directory
+  (file switches time-index wildcard full-directory-p)
   "Insert directory listing for FILE, formatted according to SWITCHES.
-Leaves point after the inserted text.
-Optional third arg WILDCARD means treat FILE as shell wildcard.
-Optional fourth arg FULL-DIRECTORY-P means file is a directory and
-switches do not contain `d', so that a full listing is expected.
-
-This version of the function comes from `ls-lisp.el'.  It does not
-run any external programs or shells.  It supports ordinary shell
-wildcards if `ls-lisp-support-shell-wildcards' variable is non-nil;
-otherwise, it interprets wildcards as regular expressions to match
-file names.
-
-Not all `ls' switches are supported.  The switches that work
-are: A a c i r S s t u"
-  (let ((handler (find-file-name-handler file 'insert-directory))
-	fattr)
-    (if handler
-	(funcall handler 'insert-directory file switches
-		 wildcard full-directory-p)
-      ;; Sometimes we get ".../foo*/" as FILE.  While the shell and
-      ;; `ls' don't mind, we certainly do, because it makes us think
-      ;; there is no wildcard, only a directory name.
-      (if (and ls-lisp-support-shell-wildcards
-	       (string-match "[[?*]" file))
-	  (progn
-	    (or (not (eq (aref file (1- (length file))) ?/))
-		(setq file (substring file 0 (1- (length file)))))
-	    (setq wildcard t)))
-      ;; Convert SWITCHES to a list of characters.
-      (setq switches (append switches nil))
-      (if wildcard
-	  (setq wildcard
-		(if ls-lisp-support-shell-wildcards
-		    (wildcard-to-regexp (file-name-nondirectory file))
-		  (file-name-nondirectory file))
-		file (file-name-directory file)))
-      (if (or wildcard
-	      full-directory-p)
-	  (let* ((dir (file-name-as-directory file))
-		 (default-directory dir);; so that file-attributes works
-		 (sum 0)
-		 elt
-		 short
-		 (file-alist (directory-files-and-attributes dir nil wildcard))
-		 (now (current-time))
-		 ;; do all bindings here for speed
-		 file-size
-		 fil attr)
-	    (cond ((memq ?A switches)
-		   (setq file-alist
-			 (ls-lisp-delete-matching "^\\.\\.?$" file-alist)))
-		  ((not (memq ?a switches))
-		   ;; if neither -A  nor -a, flush . files
-		   (setq file-alist
-			 (ls-lisp-delete-matching "^\\." file-alist))))
-	    ;; ``Total'' line (filled in afterwards).
-	    (insert (if (car-safe file-alist)
-			"total \007\n"
-		      ;; Shell says ``No match'' if no files match
-		      ;; the wildcard; let's say something similar.
-		      "(No match)\ntotal \007\n"))
-	    (setq file-alist
-		  (ls-lisp-handle-switches file-alist switches))
+Leaves point after the inserted text.  This is an internal function
+optionally called by the `ls-lisp.el' version of `insert-directory'.
+It is called recursively if the -R switch is used.
+SWITCHES is a *list* of characters.  TIME-INDEX is the time index into
+file-attributes according to SWITCHES.  WILDCARD is nil or an *Emacs
+regexp*.  FULL-DIRECTORY-P means file is a directory and SWITCHES does
+not contain `d', so that a full listing is expected."
+  ;; Sometimes we get ".../foo*/" as FILE.  While the shell and
+  ;; `ls' don't mind, we certainly do, because it makes us think
+  ;; there is no wildcard, only a directory name.
+  (if (and ls-lisp-support-shell-wildcards
+	   (string-match "[[?*]" file))
+      (progn
+	(or (not (eq (aref file (1- (length file))) ?/))
+	    (setq file (substring file 0 (1- (length file)))))
+	(setq wildcard t)))
+  (if (or wildcard full-directory-p)
+      (let* ((dir (file-name-as-directory file))
+	     (default-directory dir)	; so that file-attributes works
+	     (file-alist
+	      (directory-files-and-attributes dir nil wildcard t))
+	     (now (current-time))
+	     (sum 0)
+	     ;; do all bindings here for speed
+	     total-line files elt short file-size fil attr)
+	(cond ((memq ?A switches)
+	       (setq file-alist
+		     (ls-lisp-delete-matching "^\\.\\.?$" file-alist)))
+	      ((not (memq ?a switches))
+	       ;; if neither -A  nor -a, flush . files
+	       (setq file-alist
+		     (ls-lisp-delete-matching "^\\." file-alist))))
+	(setq file-alist
+	      (ls-lisp-handle-switches file-alist switches))
+	(if (memq ?C switches)		; column (-C) format
+	    (ls-lisp-column-format file-alist)
+	  (setq total-line (cons (point) (car-safe file-alist)))
+	  (setq files file-alist)
+	  (while files			; long (-l) format
+	    (setq elt (car files)
+		  files (cdr files)
+		  short (car elt)
+		  attr (cdr elt)
+		  file-size (nth 7 attr))
+	    (and attr
+		 (setq sum (+ file-size
+			      ;; Even if neither SUM nor file's size
+			      ;; overflow, their sum could.
+			      (if (or (< sum (- 134217727 file-size))
+				      (floatp sum)
+				      (floatp file-size))
+				  sum
+				(float sum))))
+		 (insert (ls-lisp-format short attr file-size
+					 switches time-index now))))
+	  ;; Insert total size of all files:
+	  (save-excursion
+	    (goto-char (car total-line))
+	    (or (cdr total-line)
+		;; Shell says ``No match'' if no files match
+		;; the wildcard; let's say something similar.
+		(insert "(No match)\n"))
+	    (insert (format "total %.0f\n" (fceiling (/ sum 1024.0))))))
+	(if (memq ?R switches)
+	    ;; List the contents of all directories recursively.
+	    ;; cadr of each element of `file-alist' is t for
+	    ;; directory, string (name linked to) for symbolic
+	    ;; link, or nil.
 	    (while file-alist
 	      (setq elt (car file-alist)
-		    file-alist (cdr file-alist)
-		    short (car elt)
-		    attr (cdr elt)
-		    file-size (nth 7 attr))
-	      (and attr
-		   (setq sum
-			 ;; Even if neither SUM nor file's size
-			 ;; overflow, their sum could.
-			 (if (or (< sum (- 134217727 file-size))
-				 (floatp sum)
-				 (floatp file-size))
-			     (+ sum file-size)
-			   (+ (float sum) file-size)))
-		   (insert (ls-lisp-format short attr file-size switches now))
-		   ))
-	    ;; Fill in total size of all files:
-	    (save-excursion
-	      (search-backward "total \007")
-	      (goto-char (match-end 0))
-	      (delete-char -1)
-	      (insert (format "%.0f" (fceiling (/ sum 1024.0))))))
-	;; if not full-directory-p, FILE *must not* end in /, as
-	;; file-attributes will not recognize a symlink to a directory
-	;; must make it a relative filename as ls does:
-	(if (eq (aref file (1- (length file))) ?/)
-	    (setq file (substring file 0 (1- (length file)))))
-	(setq fattr (file-attributes file))
-	(if fattr
-	    (insert (ls-lisp-format file fattr (nth 7 fattr)
-				    switches (current-time)))
-	  (message "%s: doesn't exist or is inaccessible" file)
-	  (ding)
-	  (sit-for 2))))))
+		    file-alist (cdr file-alist))
+	      (when (and (eq (cadr elt) t) ; directory
+			 (not (string-match "\\`\\.\\.?\\'" (car elt))))
+		(setq elt (expand-file-name (car elt) dir))
+		(insert "\n" elt ":\n")
+		(ls-lisp-insert-directory
+		 elt switches time-index wildcard full-directory-p)))))
+    ;; If not full-directory-p, FILE *must not* end in /, as
+    ;; file-attributes will not recognize a symlink to a directory,
+    ;; so must make it a relative filename as ls does:
+    (if (eq (aref file (1- (length file))) ?/)
+	(setq file (substring file 0 -1)))
+    (let ((fattr (file-attributes file)))
+      (if fattr
+	  (insert (ls-lisp-format file fattr (nth 7 fattr)
+				  switches time-index (current-time)))
+	(message "%s: doesn't exist or is inaccessible" file)
+	(ding) (sit-for 2)))))		; to show user the message!
+
+(defun ls-lisp-column-format (file-alist)
+  "Insert the file names (only) in FILE-ALIST into the current buffer.
+Format in columns, sorted vertically, following GNU ls -C.
+Responds to the window width as ls should but may not!"
+  (let (files fmt ncols collen (nfiles 0) (colwid 0))
+    ;; Count number of files as `nfiles', build list of filenames as
+    ;; `files', and find maximum filename length as `colwid':
+    (let (file len)
+      (while file-alist
+	(setq nfiles (1+ nfiles)
+	      file (caar file-alist)
+	      files (cons file files)
+	      file-alist (cdr file-alist)
+	      len (length file))
+	(if (> len colwid) (setq colwid len))))
+    (setq files (nreverse files)
+	  colwid (+ 2 colwid)		; 2 character column gap
+	  fmt (format "%%-%ds" colwid)	; print format
+	  ncols (/ (window-width) colwid) ; no of columns
+	  collen (/ nfiles ncols))	; floor of column length
+    (if (> nfiles (* collen ncols)) (setq collen (1+ collen)))
+    ;; Output the file names in columns, sorted vertically:
+    (let ((i 0) j)
+      (while (< i collen)
+	(setq j i)
+	(while (< j nfiles)
+	  (insert (format fmt (nth j files)))
+	  (setq j (+ j collen)))
+	;; FJW: This is completely unnecessary, but I don't like
+	;; trailing white space...
+	(delete-region (point) (progn (skip-chars-backward " \t") (point)))
+	(insert ?\n)
+	(setq i (1+ i))))))
 
 (defun ls-lisp-delete-matching (regexp list)
-  ;; Delete all elements matching REGEXP from LIST, return new list.
+  "Delete all elements matching REGEXP from LIST, return new list."
   ;; Should perhaps use setcdr for efficiency.
   (let (result)
     (while list
-      (or (string-match regexp (car (car list)))
+      (or (string-match regexp (caar list))
 	  (setq result (cons (car list) result)))
       (setq list (cdr list)))
     result))
 
+(defsubst ls-lisp-string-lessp (s1 s2)
+  "Return t if string S1 is less than string S2 in lexicographic order.
+Case is significant if `ls-lisp-ignore-case' is nil.
+Unibyte strings are converted to multibyte for comparison."
+  (let ((u (compare-strings s1 0 nil s2 0 nil ls-lisp-ignore-case)))
+    (and (numberp u) (< u 0))))
+
 (defun ls-lisp-handle-switches (file-alist switches)
+  "Return new FILE-ALIST sorted according to SWITCHES.
+SWITCHES is a list of characters.  Default sorting is alphabetic."
   ;; FILE-ALIST's elements are (FILE . FILE-ATTRIBUTES).
-  ;; Return new alist sorted according to SWITCHES which is a list of
-  ;; characters.  Default sorting is alphabetically.
-  (let (index)
-    (setq file-alist
-	  (sort file-alist
-		(cond ((memq ?S switches) ; sorted on size
-		       (function
-			(lambda (x y)
-			  ;; 7th file attribute is file size
-			  ;; Make largest file come first
-			  (< (nth 7 (cdr y))
-			     (nth 7 (cdr x))))))
-		      ((memq ?t switches) ; sorted on time
-		       (setq index (ls-lisp-time-index switches))
-		       (function
-			(lambda (x y)
-			  (ls-lisp-time-lessp (nth index (cdr y))
-					      (nth index (cdr x))))))
-		      (t		; sorted alphabetically
-		       (if ls-lisp-dired-ignore-case
-			   (function
-			    (lambda (x y)
-			      (string-lessp (upcase (car x))
-					    (upcase (car y)))))
-			 (function
-			  (lambda (x y)
-			    (string-lessp (car x)
-					  (car y))))))))))
-  (if (memq ?r switches)		; reverse sort order
-      (setq file-alist (nreverse file-alist)))
-  file-alist)
+  (or (memq ?U switches)		; unsorted
+      ;; Catch and ignore unexpected sorting errors
+      (condition-case err
+	  (setq file-alist
+		(let (index)
+		  ;; Copy file-alist in case of error
+		  (sort (copy-sequence file-alist) ; modifies its argument!
+			(cond ((memq ?S switches)
+			       (lambda (x y) ; sorted on size
+				 ;; 7th file attribute is file size
+				 ;; Make largest file come first
+				 (< (nth 7 (cdr y))
+				    (nth 7 (cdr x)))))
+			      ((setq index (ls-lisp-time-index switches))
+			       (lambda (x y) ; sorted on time
+				 (ls-lisp-time-lessp (nth index (cdr y))
+						     (nth index (cdr x)))))
+			      ((memq ?X switches)
+			       (lambda (x y) ; sorted on extension
+				 (ls-lisp-string-lessp
+				  (ls-lisp-extension (car x))
+				  (ls-lisp-extension (car y)))))
+			      (t
+			       (lambda (x y) ; sorted alphabetically
+				 (ls-lisp-string-lessp (car x) (car y))))))))
+	(error (message "Unsorted (ls-lisp sorting error) - %s"
+			(error-message-string err))
+	       (ding) (sit-for 2))))	; to show user the message!
+  (if (memq ?F switches)		; classify switch
+      (setq file-alist (mapcar 'ls-lisp-classify file-alist)))
+  (if ls-lisp-dirs-first
+  ;; Re-sort directories first, without otherwise changing the
+  ;; ordering, and reverse whole list.  cadr of each element of
+  ;; `file-alist' is t for directory, string (name linked to) for
+  ;; symbolic link, or nil.
+      (let (el dirs files)
+	(while file-alist
+	  (if (eq (cadr (setq el (car file-alist))) t) ; directory
+	      (setq dirs (cons el dirs))
+	    (setq files (cons el files)))
+	  (setq file-alist (cdr file-alist)))
+	(setq file-alist
+	      (if (memq ?U switches)	; unsorted order is reversed
+		  (nconc dirs files)
+		(nconc files dirs)
+		))))
+  ;; Finally reverse file alist if necessary.
+  ;; (eq below MUST compare `(not (memq ...))' to force comparison of
+  ;; `t' or `nil', rather than list tails!)
+  (if (eq (eq (not (memq ?U switches))	; unsorted order is reversed
+	      (not (memq ?r switches)))	; reversed sort order requested
+	  ls-lisp-dirs-first)		; already reversed
+      (nreverse file-alist)
+    file-alist))
+
+(defun ls-lisp-classify (filedata)
+  "Append a character to each file name indicating the file type.
+Also, for regular files that are executable, append `*'.
+The file type indicators are `/' for directories, `@' for symbolic
+links, `|' for FIFOs, `=' for sockets, and nothing for regular files.
+\[But FIFOs and sockets are not recognised.]
+FILEDATA has the form (filename . `file-attributes').  Its `cadr' is t
+for directory, string (name linked to) for symbolic link, or nil."
+  (let ((dir (cadr filedata)) (file-name (car filedata)))
+    (cond ((or dir
+	       ;; Parsing .lnk files here is perhaps overkill!
+	       (setq dir (ls-lisp-parse-symlink file-name)))
+	   (cons
+	    (concat file-name (if (eq dir t) "/" "@"))
+	    (cdr filedata)))
+	  ((string-match "x" (nth 9 filedata))
+	   (cons
+	    (concat file-name "*")
+	    (cdr filedata)))
+	  (t filedata))))
+
+(defun ls-lisp-extension (filename)
+  "Return extension of FILENAME (ignoring any version extension)
+FOLLOWED by null and full filename, SOLELY for full alpha sort."
+  ;; Force extension sort order: `no ext' then `null ext' then `ext'
+  ;; to agree with GNU ls.
+  (concat
+   (let* ((i (length filename)) end)
+     (if (= (aref filename (1- i)) ?.) ; null extension
+	 "\0"
+       (while (and (>= (setq i (1- i)) 0)
+		   (/= (aref filename i) ?.)))
+       (if (< i 0) "\0\0"		; no extension
+	 (if (/= (aref filename (1+ i)) ?~)
+	     (substring filename (1+ i))
+	   ;; version extension found -- ignore it
+	   (setq end i)
+	   (while (and (>= (setq i (1- i)) 0)
+		       (/= (aref filename i) ?.)))
+	   (if (< i 0) "\0\0"	; no extension
+	     (substring filename (1+ i) end))))
+       )) "\0" filename))
 
 ;; From Roland McGrath.  Can use this to sort on time.
 (defun ls-lisp-time-lessp (time0 time1)
-  (let ((hi0 (car time0))
-	(hi1 (car time1))
-	(lo0 (car (cdr time0)))
-	(lo1 (car (cdr time1))))
+  "Return t if time TIME0 is earlier than time TIME1."
+  (let ((hi0 (car time0)) (hi1 (car time1)))
     (or (< hi0 hi1)
 	(and (= hi0 hi1)
-	     (< lo0 lo1)))))
-
-
-(defun ls-lisp-format (file-name file-attr file-size switches now)
-  (let ((file-type (nth 0 file-attr)))
+	     (< (cadr time0) (cadr time1))))))
+
+(defun ls-lisp-format (file-name file-attr file-size switches time-index now)
+  "Format one line of long ls output for file FILE-NAME.
+FILE-ATTR and FILE-SIZE give the file's attributes and size.
+SWITCHES, TIME-INDEX and NOW give the full switch list and time data."
+  (let ((file-type (nth 0 file-attr))
+	;; t for directory, string (name linked to)
+	;; for symbolic link, or nil.
+	(drwxrwxrwx (nth 8 file-attr)))	; attribute string ("drwxrwxrwx")
+    (and (null file-type)
+	 ;; Maybe no kernel support for symlinks, so...
+	 (setq file-type (ls-lisp-parse-symlink file-name))
+	 (aset drwxrwxrwx 0 ?l)) ; symbolic link - update attribute string
     (concat (if (memq ?i switches)	; inode number
-		(format "%6d " (nth 10 file-attr)))
+		(format " %6d" (nth 10 file-attr)))
 	    ;; nil is treated like "" in concat
 	    (if (memq ?s switches)	; size in K
-		(format "%4.0f " (fceiling (/ file-size 1024.0))))
-	    (nth 8 file-attr)		; permission bits
-	    ;; numeric uid/gid are more confusing than helpful
+		(format " %4.0f" (fceiling (/ file-size 1024.0))))
+	    drwxrwxrwx			; attribute string
+	    (if (memq 'links ls-lisp-verbosity)
+		(format " %3d" (nth 1 file-attr))) ; link count
+	    ;; Numeric uid/gid are more confusing than helpful;
 	    ;; Emacs should be able to make strings of them.
-	    ;; user-login-name and user-full-name could take an
-	    ;; optional arg.
-	    (format (if (floatp file-size)
- 			" %3d %-8s %-8s %8.0f "
- 		      " %3d %-8s %-8s %8d ")
-		    (nth 1 file-attr)	; no. of links
-		    (if (= (user-uid) (nth 2 file-attr))
-			(user-login-name)
-		      (int-to-string (nth 2 file-attr)))	; uid
-		    (if (eq system-type 'ms-dos)
-			"root"		; everything is root on MSDOS.
-		      (int-to-string (nth 3 file-attr)))	; gid
-		    file-size
-		    )
-	    (ls-lisp-format-time file-attr switches now)
+	    ;; They tend to be bogus on non-UNIX platforms anyway so
+	    ;; optionally hide them.
+	    (if (memq 'uid ls-lisp-verbosity)
+		;; (user-login-name uid) works on Windows NT but not
+		;; on 9x and maybe not on some other platforms, so...
+		(let ((uid (nth 2 file-attr)))
+		  (if (= uid (user-uid))
+		      (format " %-8s" (user-login-name))
+		    (format " %-8d" uid))))
+	    (if (not (memq ?G switches)) ; GNU ls -- shows group by default
+		(if (or (memq ?g switches) ; UNIX ls -- no group by default
+			(memq 'gid ls-lisp-verbosity))
+		    (if (memq system-type '(macos windows-nt ms-dos))
+			;; No useful concept of group...
+			"root"
+		      (let* ((gid (nth 3 file-attr))
+			     (group (user-login-name gid)))
+			(if group
+			    (format " %-8s" group)
+			  (format " %-8d" gid))))))
+	    (format (if (floatp file-size) " %8.0f" " %8d") file-size)
+	    " "
+	    (ls-lisp-format-time file-attr time-index now)
 	    " "
 	    file-name
 	    (if (stringp file-type)	; is a symbolic link
-		(concat " -> " file-type)
-	      "")
+		(concat " -> " file-type))
 	    "\n"
 	    )))
 
 (defun ls-lisp-time-index (switches)
-  ;; Return index into file-attributes according to ls SWITCHES.
-  (cond
-   ((memq ?c switches) 6)		; last mode change
-   ((memq ?u switches) 4)		; last access
-   ;; default is last modtime
-   (t 5)))
-
-(defun ls-lisp-format-time (file-attr switches now)
-  ;; Format time string for file with attributes FILE-ATTR according
-  ;; to SWITCHES (a list of ls option letters of which c and u are recognized).
-  ;; Use the same method as `ls' to decide whether to show time-of-day or year,
-  ;; depending on distance between file date and NOW.
-  (let* ((time (nth (ls-lisp-time-index switches) file-attr))
+  "Return time index into file-attributes according to ls SWITCHES list.
+Return nil if no time switch found."
+  ;; FJW: Default of nil is IMPORTANT and used in `ls-lisp-handle-switches'!
+  (cond ((memq ?c switches) 6)		; last mode change
+	((memq ?t switches) 5)		; last modtime
+	((memq ?u switches) 4)))	; last access
+
+(defun ls-lisp-format-time (file-attr time-index now)
+  "Format time for file with attributes FILE-ATTR according to TIME-INDEX.
+Use the same method as ls to decide whether to show time-of-day or year,
+depending on distance between file date and NOW.
+All ls time options, namely c, t and u, are handled."
+  (let* ((time (nth (or time-index 5) file-attr)) ; default is last modtime
 	 (diff16 (- (car time) (car now)))
 	 (diff (+ (ash diff16 16) (- (car (cdr time)) (car (cdr now)))))
 	 (past-cutoff (- (* 6 30 24 60 60)))	; 6 30-day months