Require time-date.

(proced-command-alist, proced-command, proced-goal-header-re)
(proced-sorting-schemes-alist, proced-sorting-scheme)
(proced-header-alist, proced-sorting-schemes-re)
(proced-skip-regexp, proced-next-line, proced-previous-line)
(proced-listing-type, proced-sorting-scheme-p): Removed.
(proced-grammar-alist, proced-custom-attributes)
(proced-format-alist, proced-format, proced-filter-alist)
(proced-filter, proced-sort, proced-goal-attribute)
(proced-timer-interval, proced-timer-flag, proced-timer)
(proced-process-alist, proced-sort-internal, proced-process-tree)
(proced-header-help-echo, proced-field-help-echo): New variables.
(proced-pid-at-point, proced-timer, proced-mark-process-alist)
(proced-omit-process, proced-filter, proced-process-tree)
(proced-filter-children, proced-children-pids)
(proced-filter-parents, proced-<, proced-string-lessp)
(proced-time-lessp, proced-xor, proced-sort-p)
(proced-format-time, proced-format-start, proced-format-ttname)
(proced-format, proced-process-attributes): New functions.
(proced-toggle-timer-flag, proced-mark-children)
(proced-mark-parents, proced-filter-interactive)
(proced-filter-attribute, proced-sort-interactive)
(proced-sort-header, proced-format-interactive): New commands.
(proced-move-to-goal-column): Use goal-column.
(proced-mode): Use proced-timer.
(proced-do-mark-all): Display process count.  Use use-region-p.
Simplify.
(proced-omit-processes): Use use-region-p.
(proced-sort-pcpu, proced-sort-pmem, proced-sort-pid)
(proced-sort-start, proced-sort-time, proced-sort-user): Use
proced-sort-interactive.
(proced-sort): Make it a function that performs the actual sort.
(proced-update): New arg revert.  Use proced-process-alist,
proced-filter, proced-sort, proced-format, and
proced-grammar-alist.  Preserve position of point based on fields.
Make header line and fields clickable.
(proced-send-signal): Use proced-pid-at-point and
proced-process-alist.
(proced-why): Use save-selected-window.
(proced-log): Use buffer-read-only.

2 files changed, 999 insertions, 399 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 75ed212df39..e99988e0b7a 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,46 @@
+2008-09-06  Roland Winkler  <Roland.Winkler@physik.uni-erlangen.de>
+
+        * proced.el: Require time-date.
+        (proced-command-alist, proced-command, proced-goal-header-re)
+        (proced-sorting-schemes-alist, proced-sorting-scheme)
+        (proced-header-alist, proced-sorting-schemes-re)
+        (proced-skip-regexp, proced-next-line, proced-previous-line)
+        (proced-listing-type, proced-sorting-scheme-p): Removed.
+        (proced-grammar-alist, proced-custom-attributes)
+        (proced-format-alist, proced-format, proced-filter-alist)
+        (proced-filter, proced-sort, proced-goal-attribute)
+        (proced-timer-interval, proced-timer-flag, proced-timer)
+        (proced-process-alist, proced-sort-internal, proced-process-tree)
+        (proced-header-help-echo, proced-field-help-echo): New variables.
+        (proced-pid-at-point, proced-timer, proced-mark-process-alist)
+        (proced-omit-process, proced-filter, proced-process-tree)
+        (proced-filter-children, proced-children-pids)
+        (proced-filter-parents, proced-<, proced-string-lessp)
+        (proced-time-lessp, proced-xor, proced-sort-p)
+        (proced-format-time, proced-format-start, proced-format-ttname)
+        (proced-format, proced-process-attributes): New functions.
+        (proced-toggle-timer-flag, proced-mark-children)
+        (proced-mark-parents, proced-filter-interactive)
+        (proced-filter-attribute, proced-sort-interactive)
+        (proced-sort-header, proced-format-interactive): New commands.
+        (proced-move-to-goal-column): Use goal-column.
+        (proced-mode): Use proced-timer.
+        (proced-do-mark-all): Display process count.  Use use-region-p.
+        Simplify.
+        (proced-omit-processes): Use use-region-p.
+        (proced-sort-pcpu, proced-sort-pmem, proced-sort-pid)
+        (proced-sort-start, proced-sort-time, proced-sort-user): Use
+        proced-sort-interactive.
+        (proced-sort): Make it a function that performs the actual sort.
+        (proced-update): New arg revert.  Use proced-process-alist,
+        proced-filter, proced-sort, proced-format, and
+        proced-grammar-alist.  Preserve position of point based on fields.
+        Make header line and fields clickable.
+        (proced-send-signal): Use proced-pid-at-point and
+        proced-process-alist.
+        (proced-why): Use save-selected-window.
+        (proced-log): Use buffer-read-only.
+
 2008-09-06  Chong Yidong  <cyd@stupidchicken.com>
 
         * tooltip.el (tooltip-mode): Initialize unconditionally to t.
diff --git a/lisp/proced.el b/lisp/proced.el
index afc11e4c88b..007fe20b517 100644
--- a/lisp/proced.el
+++ b/lisp/proced.el
@@ -22,119 +22,26 @@
 
 ;;; Commentary:
 
-;; Proced makes an Emacs buffer containing a listing of the current system
-;; processes (using ps(1)).  You can use the normal Emacs commands
-;; to move around in this buffer, and special Proced commands to operate
-;; on the processes listed.
+;; Proced makes an Emacs buffer containing a listing of the current
+;; system processes.  You can use the normal Emacs commands to move around
+;; in this buffer, and special Proced commands to operate on the processes
+;; listed.
 ;;
 ;; To do:
-;; - use list-system-processes and system-process-attributes
-;; - sort and filter by user name or other criteria
-;; - make fields clickable for marking / filtering / sorting:
-;;   clicking on a USER field marks all processes of this user etc
-;;   clicking on a %MEM field marks all processes with at least this %MEM.
-;;   clicking on a header field sorts according to this header
-;; - mark parent and children PIDs (or both)
-;; - automatic update of process list
+;; - use defcustom where appropriate
+;; - interactive temporary customizability of `proced-grammar-alist'
 ;; - allow "sudo kill PID", "renice PID"
 
 ;;; Code:
 
+(require 'time-date)                 ; for `with-decoded-time-value'
+
 (defgroup proced nil
   "Proced mode."
   :group 'processes
   :group 'unix
   :prefix "proced-")
 
-;; FIXME: a better approach instead of PID-COLUMN would be based
-;; on `proced-header-alist' once we have a reliable scheme to set this variable
-(defcustom proced-command-alist
-  (cond ((memq system-type '(berkeley-unix))
-         '(("user" ("ps" "-uxgww") 2)
-           ("user-running" ("ps" "-uxrgww") 2)
-           ("all" ("ps" "-auxgww") 2)
-           ("all-running" ("ps" "-auxrgww") 2)))
-        ((memq system-type '(gnu gnu/linux)) ; BSD syntax
-         `(("user" ("ps" "uxwww") 2)
-           ("user-running" ("ps" "uxrwww") 2)
-           ("all" ("ps" "auxwww") 2)
-           ("all-running" ("ps" "auxrwww") 2)
-           ("emacs" ("ps" "--pid" ,(number-to-string (emacs-pid))
-                     "--ppid" ,(number-to-string (emacs-pid))
-                      "uwww") 2)))
-        ((memq system-type '(darwin))
-         `(("user" ("ps" "-u" ,(number-to-string (user-uid))) 2)
-           ("all" ("ps" "-Au") 2)))
-        (t ; standard UNIX syntax; doesn't allow to list running processes only
-         `(("user" ("ps" "-fu" ,(number-to-string (user-uid))) 2)
-           ("all" ("ps" "-ef") 2))))
-  "Alist of commands to get list of processes.
-Each element has the form (NAME COMMAND PID-COLUMN).
-NAME is a shorthand name to select the type of listing.
-COMMAND is a list (COMMAND-NAME ARG1 ARG2 ...),
-where COMMAND-NAME is the command to generate the listing (usually \"ps\").
-ARG1, ARG2, ... are arguments passed to COMMAND-NAME to generate
-a particular listing.  These arguments differ under various operating systems.
-PID-COLUMN is the column number (starting from 1) of the process ID."
-  :group 'proced
-  :type '(repeat (group (string :tag "name")
-                        (cons (string :tag "command")
-                              (repeat (string :tag "option")))
-                        (integer :tag "PID column"))))
-
-(defcustom proced-command (if (zerop (user-real-uid)) "all" "user")
-  "Name of process listing.
-Must be the car of an element of `proced-command-alist'."
-  :group 'proced
-  :type '(string :tag "name"))
-(make-variable-buffer-local 'proced-command)
-
-;; Should we incorporate in NAME that sorting can be done in ascending
-;; or descending order?  Then we couldn't associate NAME anymore with one
-;; of the headers in the output of ps(1).
-;; FIXME: A sorting scheme without options or with an option being a symbol
-;; should be implemented in elisp
-(defcustom proced-sorting-schemes-alist
-  (cond ((memq system-type '(gnu gnu/linux)) ; GNU long options
-         '(("%CPU" "--sort" "-pcpu") ; descending order
-           ("%MEM" "--sort" "-pmem") ; descending order
-           ("COMMAND" "--sort" "args")
-           ("PID" "--sort" "pid")
-           ("PGID,PID" "--sort" "pgid,pid")
-           ("PPID,PID" "--sort" "ppid,pid")
-           ("RSS" "--sort" "rss,pid") ; equal RSS's are rare
-           ("STAT,PID" "--sort" "stat,pid")
-           ("START" "--sort" "start_time")
-           ("TIME" "--sort" "cputime")
-           ("TTY,PID" "--sort" "tty,pid")
-           ("UID,PID" "--sort" "uid,pid")
-           ("USER,PID" "--sort" "user,pid")
-           ("VSZ,PID" "--sort" "vsz,pid"))))
-  "Alist of sorting schemes.
-Each element is a list (NAME OPTION1 OPTION2 ...).
-NAME denotes the sorting scheme.  It is the name of a header or a
-comma-separated sequence of headers in the output of ps(1).
-OPTION1, OPTION2, ... are options defining the sorting scheme."
-  :group 'proced
-  :type '(repeat (cons (string :tag "name")
-                       (repeat (string :tag "option")))))
-
-(defcustom proced-sorting-scheme nil
-  "Proced sorting type.
-Must be the car of an element of `proced-sorting-schemes-alist' or nil."
-  :group 'proced
-  :type `(choice ,@(append '((const nil)) ; sorting type may be nil
-                           (mapcar (lambda (item)
-                                     (list 'const (car item)))
-                                   proced-sorting-schemes-alist))))
-(make-variable-buffer-local 'proced-sorting-scheme)
-
-(defcustom proced-goal-header-re "\\b\\(CMD\\|COMMAND\\)\\b"
-  "If non-nil, regexp that defines the `proced-goal-column'."
-  :group 'proced
-  :type '(choice (const :tag "none" nil)
-                 (regexp :tag "regexp")))
-
 (defcustom proced-signal-function 'signal-process
   "Name of signal function.
 It can be an elisp function (usually `signal-process') or a string specifying
@@ -144,7 +51,7 @@ the external command (usually \"kill\")."
                  (string :tag "command")))
 
 (defcustom proced-signal-list
-  '(;; signals supported on all POSIX compliant systems
+  '( ;; signals supported on all POSIX compliant systems
     ("HUP   (1.  Hangup)")
     ("INT   (2.  Terminal interrupt)")
     ("QUIT  (3.  Terminal quit)")
@@ -162,7 +69,199 @@ the external command (usually \"kill\")."
   :group 'proced
   :type '(repeat (string :tag "signal")))
 
+;; For which attributes can we use a fixed width of the output field?
+;; A fixed width speeds up formatting, yet it can make
+;; `proced-grammar-alist' system-dependent.
+;; (If proced runs like top(1) we want it to be fast.)
+;;
+;; If it is impossible / unlikely that an attribute has the same value
+;; for two processes, then sorting can be based on one ordinary (fast)
+;; predicate like `<'.  Otherwise, a list of proced predicates can be used
+;; to refine the sort.
+;;
+;; It would be neat if one could temporarily override the following
+;; predefined rules.
+(defvar proced-grammar-alist
+  '( ;; attributes defined in `system-process-attributes'
+    (euid    "EUID"    "%d" right proced-< nil (euid pid) (nil t nil))
+    (user    "USER"    "%s" left proced-string-lessp nil (user pid) (nil t nil))
+    (egid    "EGID"    "%d" right proced-< nil (egid euid pid) (nil t nil))
+    (group   "GROUP"   "%s" left proced-string-lessp nil (group user pid) (nil t nil))
+    (comm    "COMMAND" "%s" left proced-string-lessp nil (comm pid) (nil t nil))
+    (state   "STAT"    "%s" left proced-string-lessp nil (state pid) (nil t nil))
+    (ppid    "PPID"    "%d" right proced-< nil (ppid pid) (nil t nil))
+    (pgrp    "PGRP"    "%d" right proced-< nil (pgrp euid pid) (nil t nil))
+    (sess    "SESS"    "%d" right proced-< nil (sess pid) (nil t nil))
+    (ttname  "TTY"     proced-format-ttname left proced-string-lessp nil (ttname pid) (nil t nil))
+    (tpgid   "TPGID"   "%d" right proced-< nil (tpgid pid) (nil t nil))
+    (minflt  "MINFLT"  "%d" right proced-< nil (minflt pid) (nil t t))
+    (majflt  "MAJFLT"  "%d" right proced-< nil (majflt pid) (nil t t))
+    (cminflt "CMINFLT" "%d" right proced-< nil (cminflt pid) (nil t t))
+    (cmajflt "CMAJFLT" "%d" right proced-< nil (cmajflt pid) (nil t t))
+    (utime   "UTIME"   proced-format-time right proced-time-lessp t (utime pid) (nil t t))
+    (stime   "STIME"   proced-format-time right proced-time-lessp t (stime pid) (nil t t))
+    (cutime  "CUTIME"  proced-format-time right proced-time-lessp t (cutime pid) (nil t t))
+    (cstime  "CSTIME"  proced-format-time right proced-time-lessp t (cstime pid) (nil t t))
+    (pri     "PR"      "%d" right proced-< t (pri pid) (nil t t))
+    (nice    "NI"      "%3d" 3 proced-< t (nice pid) (t t nil))
+    (thcount "THCOUNT" "%d" right proced-< t (thcount pid) (nil t t))
+    (start   "START"   proced-format-start 6 proced-time-lessp nil (start pid) (t t nil))
+    (vsize   "VSIZE"   "%d" right proced-< t (vsize pid) (nil t t))
+    (rss     "RSS"     "%d" right proced-< t (rss pid) (nil t t))
+    (etime   "ETIME"   proced-format-time right proced-time-lessp t (etime pid) (nil t t))
+    (pcpu    "%CPU"    "%.1f" right proced-< t (pcpu pid) (nil t t))
+    (pmem    "%MEM"    "%.1f" right proced-< t (pmem pid) (nil t t))
+    (args    "ARGS"    "%s"   left proced-string-lessp nil (args pid) (nil t nil))
+    ;;
+    ;; attributes defined by proced (see `proced-process-attributes')
+    (pid     "PID"     "%d" right proced-< nil (pid) (t t nil))
+    ;; time: sum of utime and stime
+    (time    "TIME"   proced-format-time right proced-time-lessp t (time pid) (nil t t))
+    ;; ctime: sum of cutime and cstime
+    (ctime   "CTIME"  proced-format-time right proced-time-lessp t (ctime pid) (nil t t)))
+  "Alist of rules for handling Proced attributes.
+
+Each element has the form
+
+  (KEY NAME FORMAT JUSTIFY PREDICATE REVERSE SORT-SCHEME FILTER-SCHEME).
+
+KEY is the car of a process attribute.
+
+NAME appears in the header line.
+
+FORMAT specifies the format for displaying the attribute values.
+It is either a string passed to `format' or a function called with one
+argument, the value of the attribute.
+
+If JUSTIFY is an integer, its modulus gives the width of the attribute
+vales formatted with FORMAT.  If JUSTIFY is positive, NAME appears
+right-justified, otherwise it appears left-justified.  If JUSTIFY is 'left
+or 'right, the field width is calculated from all field values in the listing.
+If JUSTIFY is 'left, the field values are formatted left-justified and
+right-justified otherwise.
+
+PREDICATE is the predicate for sorting and filtering the process listing
+based on attribute KEY.  PREDICATE takes two arguments P1 and P2,
+the corresponding attribute values of two processes.  PREDICATE should
+return 'equal if P1 has same rank like P2.  Any other non-nil value says
+that P1 is \"less than\" P2, or nil if not.
+
+REVERSE is non-nil if the sort order is opposite to the order defined
+by PREDICATE.
+
+SORT-SCHEME is a list (KEY1 KEY2 ...) defing a hierarchy of rules
+for sorting the process listing.  KEY1, KEY2, ... are KEYs appearing as cars
+of `proced-grammar-alist'.  First the PREDICATE of KEY1 is evaluated.
+If it yields non-equal, it defines the sorting order for the corresponding
+processes.  If it evaluates to 'equal the PREDICATE of KEY2 is evaluated, etc.
+
+FILTER-SCHEME is a list (LESS-B EQUAL-B LARGER-B) used by the command
+`proced-filter-attribute' for filtering KEY (see there).  This command
+compares the value of attribute KEY of every process with the value
+of attribute KEY of the process at the position of point using PREDICATE.
+If PREDICATE yields non-nil, the process is accepted if LESS-B is non-nil.
+If PREDICATE yields 'equal, the process is accepted if EQUAL-B is non-nil.
+If PREDICATE yields nil, the process is accepted if LARGER-B is non-nil.")
+
+(defvar proced-custom-attributes nil
+  "List of functions defining custom attributes.
+This variable extends the functionality of `proced-process-attributes'.
+Each function is called with one argument, the list of attributes
+of a system process.  It returns a cons cell of the form (KEY . VALUE)
+like `system-process-attributes'.")
+
+;; Formatting and sorting rules are defined "per attribute".  If formatting
+;; and / or sorting should use more than one attribute, it appears more
+;; transparent to define a new derived attribute, so that formatting and
+;; sorting can use them consistently.  (Are there exceptions to this rule?
+;; Would it be advantageous to have yet more general methods available?)
+;; Sorting can also be based on attributes that are invisible in the listing.
+
+(defvar proced-format-alist
+  '((short user pid pcpu pmem start time args)
+    (medium user pid pcpu pmem vsize rss ttname state start time args)
+    (long user euid group pid pri nice pcpu pmem vsize rss ttname state
+          start time args)
+    (verbose user euid group egid pid ppid pgrp sess comm pri nice pcpu pmem
+             state thcount vsize rss ttname tpgid minflt majflt cminflt cmajflt
+             start time utime stime ctime cutime cstime etime args))
+  "Alist of formats of listing.
+The car of each element is a symbol, the name of the format.
+The cdr is a list of keys appearing in `proced-grammar-alist'.")
+
+(defvar proced-format 'short
+  "Current format of Proced listing.
+It can be the car of an element of `proced-format-alist'.
+It can also be a list of keys appearing in `proced-grammar-alist'.")
+(make-variable-buffer-local 'proced-format)
+
+;; FIXME: is there a better name for filter `user' that does not coincide
+;; with an attribute key?
+(defvar proced-filter-alist
+  `((user (user . ,(concat "\\`" (user-real-login-name) "\\'")))
+    (user-running (user . ,(concat "\\`" (user-real-login-name) "\\'"))
+                  (state . "\\`[Rr]\\'"))
+    (all)
+    (all-running (state . "\\`[Rr]\\'"))
+    (emacs (fun-all . (lambda (list)
+                        (proced-filter-children list ,(emacs-pid))))))
+  "Alist of process filters.
+The car of each element is a symbol, the name of the filter.
+The cdr is a list of elementary filters that are applied to every process.
+A process is displayed if it passes all elementary filters of a selected
+filter.
+
+An elementary filter can be one of the following:
+\(KEY . REGEXP)   If value of attribute KEY matches REGEXP,
+                 accept this process.
+\(KEY . FUN)      Apply function FUN to attribute KEY.  Accept this process,
+                 if FUN returns non-nil.
+\(function . FUN) For each process, apply function FUN to list of attributes
+                 of each.  Accept the process if FUN returns non-nil.
+\(fun-all . FUN)  Apply function FUN to entire process list.
+                 FUN must return the filtered list.")
+
+(defvar proced-filter 'user
+  "Current filter of proced listing.
+It can be the car of an element of `proced-filter-alist'.
+It can also be a list of elementary filters as in the cdrs of the elements
+of `proced-filter-alist'.")
+(make-variable-buffer-local 'proced-filter)
+
+(defvar proced-sort 'pcpu
+  "Current sorting scheme for proced listing.
+It must be the KEY of an element of `proced-grammar-alist'.
+It can also be a list of KEYs as in the SORT-SCHEMEs of the elements
+of `proced-grammar-alist'.")
+(make-variable-buffer-local 'proced-format)
+
+(defcustom proced-goal-attribute 'args
+  "If non-nil, key of the attribute that defines the `goal-column'."
+  :group 'proced
+  :type '(choice (const :tag "none" nil)
+                 (symbol :tag "key")))
+
+(defcustom proced-timer-interval 5
+  "Time interval in seconds for updating Proced buffers."
+  :group 'proced
+  :type 'integer)
+
+(defcustom proced-timer-flag nil
+  "Non-nil for regular update of a Proced buffer.
+Can be changed interactively via `proced-toggle-timer-flag'."
+  :group 'proced
+  :type 'boolean)
+(make-variable-buffer-local 'proced-timer-flag)
+
 ;; Internal variables
+
+(defvar proced-process-alist nil
+  "Alist of PIDs displayed by Proced.")
+(make-variable-buffer-local 'proced-process-alist)
+
+(defvar proced-sort-internal nil
+  "Sorting scheme for listing (internal format).")
+
 (defvar proced-marker-char ?*           ; the answer is 42
   "In proced, the current mark character.")
 
@@ -190,9 +289,30 @@ the external command (usually \"kill\")."
   "Regexp matching a marked line.
 Important: the match ends just after the marker.")
 
-(defvar proced-goal-column nil
-  "Proced goal column.  Initialized based on `proced-goal-header-re'.")
-(make-variable-buffer-local 'proced-goal-column)
+(defvar proced-header-line nil
+  "Headers in Proced buffer as a string.")
+(make-variable-buffer-local 'proced-header-line)
+
+(defvar proced-log-buffer "*Proced log*"
+  "Name of Proced Log buffer.")
+
+(defvar proced-process-tree nil
+  "Process tree of listing (internal variable).")
+
+(defvar proced-timer nil
+  "Stores if Proced timer is already installed.")
+
+(defconst proced-help-string
+  "(n)ext, (p)revious, (m)ark, (u)nmark, (k)ill, (q)uit (type ? for more help)"
+  "Help string for proced.")
+
+(defconst proced-header-help-echo
+  "mouse-2: sort by attribute %s%s"
+  "Help string shown when mouse is over a sortable header.")
+
+(defconst proced-field-help-echo
+  "mouse-2, RET: filter by attribute %s %s"
+  "Help string shown when mouse is over a filterable field.")
 
 (defvar proced-font-lock-keywords
   (list
@@ -208,35 +328,44 @@ Important: the match ends just after the marker.")
   (let ((km (make-sparse-keymap)))
     ;; moving
     (define-key km " " 'proced-next-line)
-    (define-key km "n" 'proced-next-line)
-    (define-key km "p" 'proced-previous-line)
-    (define-key km "\C-n" 'proced-next-line)
-    (define-key km "\C-p" 'proced-previous-line)
-    (define-key km "\C-?" 'proced-previous-line)
-    (define-key km [down] 'proced-next-line)
-    (define-key km [up] 'proced-previous-line)
+    (define-key km "n" 'next-line)
+    (define-key km "p" 'previous-line)
+    (define-key km "\C-n" 'next-line)
+    (define-key km "\C-p" 'previous-line)
+    (define-key km "\C-?" 'previous-line)
+    (define-key km [down] 'next-line)
+    (define-key km [up] 'previous-line)
     ;; marking
-    (define-key km "d" 'proced-mark) ; Dired compatibility
+    (define-key km "d" 'proced-mark) ; Dired compatibility ("delete")
     (define-key km "m" 'proced-mark)
     (define-key km "u" 'proced-unmark)
     (define-key km "\177" 'proced-unmark-backward)
     (define-key km "M" 'proced-mark-all)
     (define-key km "U" 'proced-unmark-all)
     (define-key km "t" 'proced-toggle-marks)
+    (define-key km "C" 'proced-mark-children)
+    (define-key km "P" 'proced-mark-parents)
+    ;; filtering
+    (define-key km "f"  'proced-filter-interactive)
+    (define-key km [mouse-2] 'proced-filter-attribute)
+    (define-key km "\C-m" 'proced-filter-attribute)
     ;; sorting
     (define-key km "sc" 'proced-sort-pcpu)
     (define-key km "sm" 'proced-sort-pmem)
     (define-key km "sp" 'proced-sort-pid)
     (define-key km "ss" 'proced-sort-start)
-    (define-key km "sS" 'proced-sort)
+    (define-key km "sS" 'proced-sort-interactive)
     (define-key km "st" 'proced-sort-time)
+    (define-key km "su" 'proced-sort-user)
+    (define-key km [header-line mouse-2] 'proced-sort-header)
+    ;; formatting
+    (define-key km "F"  'proced-format-interactive)
     ;; operate
     (define-key km "o" 'proced-omit-processes)
     (define-key km "x" 'proced-send-signal) ; Dired compatibility
     (define-key km "k" 'proced-send-signal) ; kill processes
     ;; misc
-    (define-key km "l" 'proced-listing-type)
-    (define-key km "g" 'revert-buffer) ; Dired compatibility
+    (define-key km "g" 'revert-buffer)  ; Dired compatibility
     (define-key km "h" 'describe-mode)
     (define-key km "?" 'proced-help)
     (define-key km "q" 'quit-window)
@@ -258,54 +387,52 @@ Important: the match ends just after the marker.")
      :help "Unmark All Process"]
     ["Toggle Marks" proced-toggle-marks
      :help "Marked Processes Become Unmarked, and Vice Versa"]
+    ["Mark Children" proced-mark-children
+     :help "Mark Current Process and its Children"]
+    ["Mark Parents" proced-mark-parents
+     :help "Mark Current Process and its Parents"]
     "--"
-    ["Sort..." proced-sort
-     :help "Sort Process List"]
-    ["Sort by %CPU" proced-sort-pcpu (proced-sorting-scheme-p "%CPU")]
-    ["Sort by %MEM" proced-sort-pmem (proced-sorting-scheme-p "%MEM")]
-    ["Sort by PID" proced-sort-pid (proced-sorting-scheme-p "PID")]
-    ["Sort by START" proced-sort-start (proced-sorting-scheme-p "START")]
-    ["Sort by TIME" proced-sort-time (proced-sorting-scheme-p "TIME")]
+    ("Filters"
+     :help "Select Filter for Process Listing"
+     ,@(mapcar (lambda (el)
+                 (let ((filter (car el)))
+                   `[,(symbol-name filter)
+                     (proced-filter-interactive ',filter)
+                     :style radio
+                     :selected (eq proced-filter ',filter)]))
+               proced-filter-alist))
+    ("Sorting"
+     :help "Select Sorting Scheme"
+     ["Sort..." proced-sort-interactive
+      :help "Sort Process List"]
+     "--"
+     ["Sort by %CPU" proced-sort-pcpu]
+     ["Sort by %MEM" proced-sort-pmem]
+     ["Sort by PID" proced-sort-pid]
+     ["Sort by START" proced-sort-start]
+     ["Sort by TIME" proced-sort-time]
+     ["Sort by USER" proced-sort-user])
+    ("Formats"
+     :help "Select Format for Process Listing"
+     ,@(mapcar (lambda (el)
+                 (let ((format (car el)))
+                   `[,(symbol-name format)
+                     (proced-format-interactive ',format)
+                     :style radio
+                     :selected (eq proced-format ',format)]))
+               proced-format-alist))
     "--"
     ["Omit Marked Processes" proced-omit-processes
      :help "Omit Marked Processes in Process Listing."]
     "--"
     ["Revert" revert-buffer
      :help "Revert Process Listing"]
+    ["Regular Update" proced-toggle-timer-flag
+     :style radio
+     :selected (eval proced-timer-flag)
+     :help "Regular Update of Proced buffer"]
     ["Send signal" proced-send-signal
-     :help "Send Signal to Marked Processes"]
-    ("Listing Type"
-     :help "Select Type of Process Listing"
-     ,@(mapcar (lambda (el)
-                 (let ((command (car el)))
-                   `[,command (proced-listing-type ,command)
-                             :style radio
-                             :selected (string= proced-command ,command)]))
-               proced-command-alist))))
-
-(defconst proced-help-string
-  "(n)ext, (p)revious, (m)ark, (u)nmark, (k)ill, (q)uit  (type ? for more help)"
-  "Help string for proced.")
-
-(defvar proced-header-line nil
-  "Headers in Proced buffer as a string.")
-(make-variable-buffer-local 'proced-header-line)
-
-(defvar proced-header-alist nil
-  "Alist of headers in Proced buffer.
-Each element is of the form (NAME START END JUSTIFY).
-NAME is name of header in the output of ps(1).
-START and END are column numbers starting from 0.
-END is t if there is no end column for that field.
-JUSTIFY is 'left or 'right for left or right-justified output of ps(1).")
-(make-variable-buffer-local 'proced-header-alist)
-
-(defvar proced-sorting-schemes-re nil
-  "Regexp to match valid sorting schemes.")
-(make-variable-buffer-local 'proced-sorting-schemes-re)
-
-(defvar proced-log-buffer "*Proced log*"
-  "Name of Proced Log buffer.")
+     :help "Send Signal to Marked Processes"]))
 
 ;; helper functions
 (defun proced-marker-regexp ()
@@ -317,20 +444,37 @@ JUSTIFY is 'left or 'right for left or right-justified output of ps(1).")
   "Display success message for ACTION performed for COUNT processes."
   (message "%s %s process%s" action count (if (= 1 count) "" "es")))
 
+;; Unlike dired, we do not define our own commands for vertical motion.
+;; If `goal-column' is set, `next-line' and `previous-line' are fancy
+;; commands to satisfy our modest needs.  If `proced-goal-attribute'
+;; and/or `goal-column' are not set, `next-line' and `previous-line'
+;; are really what we need to preserve the column of point.
+;; We use `proced-move-to-goal-column' for "non-interactive" cases only
+;; to get a well-defined position of point.
+
 (defun proced-move-to-goal-column ()
-  "Move to `proced-goal-column' if non-nil."
+  "Move to `goal-column' if non-nil."
   (beginning-of-line)
-  (if proced-goal-column
-      (forward-char proced-goal-column)
-    (forward-char 2)))
-
-;; FIXME: a better approach would be based on `proced-header-alist'
-;; once we have a reliable scheme to set this variable
-(defsubst proced-skip-regexp ()
-  "Regexp to skip in process listing to find PID column."
-  (apply 'concat (make-list (1- (nth 2 (assoc proced-command
-                                              proced-command-alist)))
-                            "\\s-+\\S-+")))
+  (unless (eobp)
+    (if goal-column
+        (forward-char goal-column)
+      (forward-char 2))))
+
+(defun proced-header-line ()
+  "Return header line for Proced buffer."
+  (list (propertize " " 'display '(space :align-to 0))
+        (replace-regexp-in-string ;; preserve text properties
+         "\\(%\\)" "\\1\\1" (substring proced-header-line (window-hscroll)))))
+
+(defun proced-pid-at-point ()
+  "Return pid of system process at point.
+Return nil if point is not on a process line."
+  (save-excursion
+    (beginning-of-line)
+    (if (looking-at "^. .")
+        (get-text-property (match-end 0) 'proced-pid))))
+
+;; proced mode
 
 (define-derived-mode proced-mode nil "Proced"
   "Mode for displaying UNIX system processes and sending signals to them.
@@ -346,7 +490,10 @@ Type \\[proced-send-signal] to send signals to marked processes.
   (add-hook 'post-command-hook 'force-mode-line-update nil t)
   (set (make-local-variable 'revert-buffer-function) 'proced-revert)
   (set (make-local-variable 'font-lock-defaults)
-       '(proced-font-lock-keywords t nil nil beginning-of-line)))
+       '(proced-font-lock-keywords t nil nil beginning-of-line))
+  (if (and (not proced-timer) proced-timer-interval)
+      (setq proced-timer
+            (run-at-time t proced-timer-interval 'proced-timer))))
 
 ;; Proced mode is suitable only for specially formatted data.
 (put 'proced-mode 'mode-class 'special)
@@ -367,7 +514,7 @@ information will be displayed but not selected.
     (setq new (zerop (buffer-size)))
     (if new (proced-mode))
     (if (or new arg)
-        (proced-update))
+        (proced-update t))
     (if arg
         (display-buffer buffer)
       (pop-to-buffer buffer)
@@ -375,19 +522,25 @@ information will be displayed but not selected.
        (substitute-command-keys
         "Type \\<proced-mode-map>\\[quit-window] to quit, \\[proced-help] for help")))))
 
-(defun proced-next-line (arg)
-  "Move down lines then position at `proced-goal-column'.
-Optional prefix ARG says how many lines to move; default is one line."
-  (interactive "p")
-  (forward-line arg)
-  (proced-move-to-goal-column))
-
-(defun proced-previous-line (arg)
-  "Move up lines then position at `proced-goal-column'.
-Optional prefix ARG says how many lines to move; default is one line."
-  (interactive "p")
-  (forward-line (- arg))
-  (proced-move-to-goal-column))
+(defun proced-timer ()
+  "Update Proced buffers regularly using `run-at-time'."
+  (dolist (buf (buffer-list))
+    (with-current-buffer buf
+      (if (and (eq major-mode 'proced-mode)
+               proced-timer-flag)
+          (proced-update t t)))))
+
+(defun proced-toggle-timer-flag (arg)
+  "Change whether this Proced buffer is updated regularly.
+With prefix ARG, update this buffer regularly if ARG is positive,
+otherwise do not update.  Sets the variable `proced-timer-flag'.
+The time interval for updates is specified via `proced-timer-interval'."
+  (interactive (list (or current-prefix-arg 'toggle)))
+  (setq proced-timer-flag
+        (cond ((eq arg 'toggle) (not proced-timer-flag))
+              (arg (> (prefix-numeric-value arg) 0))
+              (t (not proced-timer-flag))))
+  (message "`proced-timer-flag' set to %s" proced-timer-flag))
 
 (defun proced-mark (&optional count)
   "Mark the current (or next COUNT) processes."
@@ -436,23 +589,24 @@ unmark the region."
   "Mark all processes using MARK.
 If `transient-mark-mode' is turned on and the region is active,
 mark the region."
-  (let (buffer-read-only)
+  (let ((count 0) end buffer-read-only)
     (save-excursion
-      (if (and transient-mark-mode mark-active)
+      (if (use-region-p)
           ;; Operate even on those lines that are only partially a part
           ;; of region.  This appears most consistent with
           ;; `proced-move-to-goal-column'.
-          (let ((end (save-excursion
-                       (goto-char (region-end))
-                       (unless (looking-at "^") (forward-line))
-                       (point))))
-            (goto-char (region-beginning))
-            (unless (looking-at "^") (beginning-of-line))
-            (while (< (point) end)
-              (proced-insert-mark mark)))
+          (progn (setq end (save-excursion
+                             (goto-char (region-end))
+                             (unless (looking-at "^") (forward-line))
+                             (point)))
+                 (goto-char (region-beginning))
+                 (unless (looking-at "^") (beginning-of-line)))
         (goto-char (point-min))
-        (while (not (eobp))
-          (proced-insert-mark mark))))))
+        (setq end (point-max)))
+      (while (< (point) end)
+        (setq count (1+ count))
+        (proced-insert-mark mark))
+      (proced-success-message "Marked" count))))
 
 (defun proced-toggle-marks ()
   "Toggle marks: marked processes become unmarked, and vice versa."
@@ -478,152 +632,613 @@ Otherwise move one line forward after inserting the mark."
   (delete-char 1)
   (unless backward (forward-line)))
 
+(defun proced-mark-children (ppid &optional omit-ppid)
+  "Mark child processes of process PPID.
+Also mark process PPID unless prefix OMIT-PPID is non-nil."
+  (interactive (list (proced-pid-at-point) current-prefix-arg))
+  (proced-mark-process-alist
+   (proced-filter-children proced-process-alist ppid omit-ppid)))
+
+(defun proced-mark-parents (cpid &optional omit-cpid)
+  "Mark parent processes of process CPID.
+Also mark CPID unless prefix OMIT-CPID is non-nil."
+  (interactive (list (proced-pid-at-point) current-prefix-arg))
+  (proced-mark-process-alist
+   (proced-filter-parents proced-process-alist cpid omit-cpid)))
+
+(defun proced-mark-process-alist (process-alist &optional quiet)
+  (let ((count 0))
+    (if process-alist
+        (let (buffer-read-only)
+          (save-excursion
+            (goto-char (point-min))
+            (while (not (eobp))
+              (when (assq (proced-pid-at-point) process-alist)
+                (insert proced-marker-char)
+                (delete-char 1)
+                (setq count (1+ count)))
+              (forward-line)))))
+    (unless quiet
+      (proced-success-message "Marked" count))))
+
 ;; Mostly analog of `dired-do-kill-lines'.
 ;; However, for negative args the target lines of `dired-do-kill-lines'
 ;; include the current line, whereas `dired-mark' for negative args operates
-;; on the preceding lines. Here we are consistent with `dired-mark'.
+;; on the preceding lines.  Here we are consistent with `dired-mark'.
 (defun proced-omit-processes (&optional arg quiet)
   "Omit marked processes.
 With prefix ARG, omit that many lines starting with the current line.
 \(A negative argument omits backward.)
+If `transient-mark-mode' is turned on and the region is active,
+omit the processes in region.
 If QUIET is non-nil suppress status message.
 Returns count of omitted lines."
   (interactive "P")
   (let ((mark-re (proced-marker-regexp))
         (count 0)
         buffer-read-only)
-    (if arg
-        ;; Omit ARG lines starting with the current line.
-        (delete-region (line-beginning-position)
-                       (save-excursion
-                         (if (<= 0 arg)
-                             (setq count (- arg (forward-line arg)))
-                           (setq count (min (1- (line-number-at-pos))
-                                            (abs arg)))
-                           (forward-line (- count)))
-                         (point)))
-        ;; Omit marked lines
-      (save-excursion
-        (goto-char (point-min))
-        (while (and (not (eobp))
-                    (re-search-forward mark-re nil t))
-          (delete-region (match-beginning 0)
-                         (save-excursion (forward-line) (point)))
-          (setq count (1+ count)))))
+    (cond ((use-region-p) ;; Omit active region
+           (let ((lines (count-lines (region-beginning) (region-end))))
+             (save-excursion
+               (goto-char (region-beginning))
+               (while (< count lines)
+                 (proced-omit-process)
+                 (setq count (1+ count))))))
+          ((not arg) ;; Omit marked lines
+           (save-excursion
+             (goto-char (point-min))
+             (while (and (not (eobp))
+                         (re-search-forward mark-re nil t))
+               (proced-omit-process)
+               (setq count (1+ count)))))
+          ((< 0 arg) ;; Omit forward
+           (while (and (not (eobp)) (< count arg))
+             (proced-omit-process)
+             (setq count (1+ count))))
+          ((< arg 0) ;; Omit backward
+           (while (and (not (bobp)) (< count (- arg)))
+             (forward-line -1)
+             (proced-omit-process)
+             (setq count (1+ count)))))
     (unless (zerop count) (proced-move-to-goal-column))
     (unless quiet (proced-success-message "Omitted" count))
     count))
 
-(defun proced-listing-type (command)
-  "Select `proced' listing type COMMAND from `proced-command-alist'."
+(defun proced-omit-process ()
+  "Omit process from listing point is on.
+Update `proced-process-alist' accordingly."
+  (setq proced-process-alist
+        (assq-delete-all (proced-pid-at-point) proced-process-alist))
+  (delete-region (line-beginning-position)
+                 (save-excursion (forward-line) (point))))
+
+;;; Filtering
+
+(defun proced-filter (process-alist filter-list)
+  "Apply FILTER-LIST to PROCESS-ALIST."
+  (if (symbolp filter-list)
+      (setq filter-list (cdr (assq filter-list proced-filter-alist))))
+  (dolist (filter filter-list)
+    (let (new-alist)
+      (cond ( ;; apply function to entire process list
+             (eq (car filter) 'fun-all)
+             (setq new-alist (funcall (cdr filter) process-alist)))
+            ( ;; apply predicate to each list of attributes
+             (eq (car filter) 'function)
+             (dolist (process process-alist)
+               (if (funcall (car filter) (cdr process))
+                   (push process new-alist))))
+            (t ;; apply predicate to specified attribute
+             (let ((fun (if (stringp (cdr filter))
+                            `(lambda (val)
+                               (string-match ,(cdr filter) val))
+                          (cdr filter)))
+                   value)
+               (dolist (process process-alist)
+                 (setq value (cdr (assq (car filter) (cdr process))))
+                 (if (and value (funcall fun value))
+                     (push process new-alist))))))
+      (setq process-alist new-alist)))
+  process-alist)
+
+(defun proced-filter-interactive (scheme &optional revert)
+  "Filter Proced buffer using SCHEME.
+When called interactively, an empty string means nil, i.e., no filtering.
+With prefix REVERT non-nil revert listing."
   (interactive
-   (list (completing-read "Listing type: " proced-command-alist nil t)))
-  (setq proced-command command)
-  (proced-update))
+   (let ((scheme (completing-read "Filter: "
+                                  proced-filter-alist nil t)))
+     (list (if (string= "" scheme) nil (intern scheme))
+           current-prefix-arg)))
+  (setq proced-filter scheme)
+  (proced-update revert))
+
+(defun proced-process-tree (process-alist)
+  "Return process tree for PROCESS-ALIST.
+The process tree is an alist with elements (PPID PID1 PID2 ...).
+PPID is a parent PID.  PID1, PID2, ... are the child processes of PPID.
+The list of children does not include grandchildren."
+  (let (children-list ppid cpids)
+    (dolist (process process-alist children-list)
+      (setq ppid (cdr (assq 'ppid (cdr process))))
+      (if ppid
+          (setq children-list
+                (if (setq cpids (assq ppid children-list))
+                    (cons (cons ppid (cons (car process) (cdr cpids)))
+                          (assq-delete-all ppid children-list))
+                  (cons (list ppid (car process))
+                        children-list)))))))
+
+(defun proced-filter-children (process-alist ppid &optional omit-ppid)
+  "For PROCESS-ALIST return list of child processes of PPID.
+This list includes PPID unless OMIT-PPID is non-nil."
+  (let ((proced-process-tree (proced-process-tree process-alist))
+        new-alist)
+    (dolist (pid (proced-children-pids ppid))
+      (push (assq pid process-alist) new-alist))
+    (if omit-ppid
+        (assq-delete-all ppid new-alist)
+      new-alist)))
+
+;; helper function
+(defun proced-children-pids (ppid)
+  "Return list of children PIDs of PPID (including PPID)."
+  (let ((cpids (cdr (assq ppid proced-process-tree))))
+    (if cpids
+        (cons ppid (apply 'append (mapcar 'proced-children-pids cpids)))
+      (list ppid))))
+
+(defun proced-filter-parents (process-alist pid &optional omit-pid)
+  "For PROCESS-ALIST return list of parent processes of PID.
+This list includes CPID unless OMIT-CPID is non-nil."
+  (let ((parent-list (unless omit-pid (list (assq pid process-alist)))))
+    (while (setq pid (cdr (assq 'ppid (cdr (assq pid process-alist)))))
+      (push (assq pid process-alist) parent-list))
+    parent-list))
+
+(defun proced-filter-attribute (&optional event)
+  "Filter Proced listing based on the attribute at point.
+Optional EVENT is the location of the Proced field."
+  (interactive (list last-input-event))
+  (if event (posn-set-point (event-end event)))
+  (let ((key (get-text-property (point) 'proced-key))
+        (pid (get-text-property (point) 'proced-pid)))
+    (if (and key pid)
+        (let* ((grammar (assq key proced-grammar-alist))
+               (predicate (nth 4 grammar))
+               (filter (nth 7 grammar))
+               (ref (cdr (assq key (cdr (assq pid proced-process-alist)))))
+               val new-alist)
+          (when ref
+            (dolist (process proced-process-alist)
+              (setq val (funcall predicate (cdr (assq key (cdr process))) ref))
+              (if (cond ((not val) (nth 2 filter))
+                        ((eq val 'equal) (nth 1 filter))
+                        (val (car filter)))
+                  (push process new-alist)))
+            (setq proced-process-alist new-alist)
+            (proced-update)))
+      (message "No filter defined here."))))
+
+;; Proced predicates for sorting and filtering are based on a three-valued
+;; logic:
+;; Predicates takes two arguments P1 and P2, the corresponding attribute
+;; values of two processes.  Predicate should return 'equal if P1 has
+;; same rank like P2.  Any other non-nil value says that P1 is "less than" P2,
+;; or nil if not.
+
+(defun proced-< (num1 num2)
+  "Return t if NUM1 less than NUM2.
+Return `equal' if NUM1 equals NUM2.  Return nil if NUM1 greater than NUM2."
+  (if (= num1 num2)
+      'equal
+    (< num1 num2)))
+
+(defun proced-string-lessp (s1 s2)
+  "Return t if string S1 is less than S2 in lexicographic order.
+Return `equal' if S1 and S2 have identical contents.
+Return nil otherwise."
+  (if (string= s1 s2)
+      'equal
+    (string-lessp s1 s2)))
+
+(defun proced-time-lessp (t1 t2)
+  "Return t if time value T1 is less than time value T2.
+Return `equal' if T1 equals T2.  Return nil otherwise."
+  (with-decoded-time-value ((high1 low1 micro1 t1)
+                            (high2 low2 micro2 t2))
+    (cond ((< high1 high2))
+          ((< high2 high1) nil)
+          ((< low1 low2))
+          ((< low2 low1) nil)
+          ((< micro1 micro2))
+          ((< micro2 micro1) nil)
+          (t 'equal))))
 
-(defun proced-header-line ()
-  "Return header line for Proced buffer."
-  (list (propertize " " 'display '(space :align-to 0))
-        (replace-regexp-in-string
-         "%" "%%" (substring proced-header-line (window-hscroll)))))
+;;; Sorting
+
+(defsubst proced-xor (b1 b2)
+  "Return the logical exclusive or of args B1 and B2."
+  (and (or b1 b2)
+       (not (and b1 b2))))
+
+(defun proced-sort-p (p1 p2)
+  "Predicate for sorting processes P1 and P2."
+  (if (not (cdr proced-sort-internal))
+      ;; only one predicate: fast scheme
+      (let* ((sorter (car proced-sort-internal))
+             (k1 (cdr (assq (car sorter) (cdr p1))))
+             (k2 (cdr (assq (car sorter) (cdr p2)))))
+        ;; if the attributes are undefined, we should really abort sorting
+        (if (and k1 k2)
+            (proced-xor (funcall (nth 1 sorter) k1 k2)
+                        (nth 2 sorter))))
+    (let ((sort-list proced-sort-internal) sorter predicate k1 k2)
+      (catch 'done
+        (while (setq sorter (pop sort-list))
+          (setq k1 (cdr (assq (car sorter) (cdr p1)))
+                k2 (cdr (assq (car sorter) (cdr p2)))
+                predicate
+                (if (and k1 k2)
+                    (funcall (nth 1 sorter) k1 k2)))
+          (if (not (eq predicate 'equal))
+              (throw 'done (proced-xor predicate (nth 2 sorter)))))
+        (eq t predicate)))))
+
+(defun proced-sort (process-alist sorter)
+  "Sort PROCESS-ALIST using scheme SORTER.
+Return sorted process list."
+  ;; translate SORTER into a list of lists (KEY PREDICATE REVERSE)
+  (setq proced-sort-internal
+        (mapcar (lambda (arg)
+                  (let ((grammar (assq arg proced-grammar-alist)))
+                    (list arg (nth 4 grammar) (nth 5 grammar))))
+                (cond ((listp sorter) sorter)
+                      ((and (symbolp sorter)
+                            (nth 6 (assq sorter proced-grammar-alist))))
+                      ((symbolp sorter) (list sorter))
+                      (t (error "Sorter undefined %s" sorter)))))
+  (if proced-sort-internal
+      (sort process-alist 'proced-sort-p)
+    process-alist))
+
+(defun proced-sort-interactive (scheme &optional revert)
+  "Sort Proced buffer using SCHEME.
+When called interactively, an empty string means nil, i.e., no sorting.
+With prefix REVERT non-nil revert listing."
+  (interactive
+   (let ((scheme (completing-read "Sorting type: "
+                                  proced-grammar-alist nil t)))
+     (list (if (string= "" scheme) nil (intern scheme))
+           current-prefix-arg)))
+  (setq proced-sort scheme)
+  (proced-update revert))
+
+(defun proced-sort-pcpu (&optional revert)
+  "Sort Proced buffer by percentage CPU time (%CPU)."
+  (interactive "P")
+  (proced-sort-interactive 'pcpu revert))
+
+(defun proced-sort-pmem (&optional revert)
+  "Sort Proced buffer by percentage memory usage (%MEM)."
+  (interactive "P")
+  (proced-sort-interactive 'pmem))
+
+(defun proced-sort-pid (&optional revert)
+  "Sort Proced buffer by PID."
+  (interactive "P")
+  (proced-sort-interactive 'pid revert))
+
+(defun proced-sort-start (&optional revert)
+  "Sort Proced buffer by time the command started (START)."
+  (interactive "P")
+  (proced-sort-interactive 'start revert))
+
+(defun proced-sort-time (&optional revert)
+  "Sort Proced buffer by CPU time (TIME)."
+  (interactive "P")
+  (proced-sort-interactive 'time revert))
+
+(defun proced-sort-user (&optional revert)
+  "Sort Proced buffer by USER."
+  (interactive "P")
+  (proced-sort-interactive 'user revert))
+
+(defun proced-sort-header (event &optional revert)
+  "Sort Proced listing based on an attribute.
+EVENT is a mouse event with starting position in the header line.
+It is converted in the corresponding attribute key."
+  (interactive "e\nP")
+  (let ((start (event-start event))
+        col key)
+    (save-selected-window
+      (select-window (posn-window start))
+      (setq col (+ (1- (car (posn-col-row start)))
+                   (window-hscroll)))
+      (when (and (<= 0 col) (< col (length proced-header-line)))
+        (setq key (get-text-property col 'proced-key proced-header-line))
+        (if key
+            (proced-sort-interactive key revert)
+          (message "No sorter defined here."))))))
+
+;;; Formating
+
+(defun proced-format-time (time)
+  "Format time intervall TIME."
+  (let* ((ftime (float-time time))
+         (days (truncate ftime 86400))
+         (ftime (mod ftime 86400))
+         (hours (truncate ftime 3600))
+         (ftime (mod ftime 3600))
+         (minutes (truncate ftime 60))
+         (seconds (mod ftime 60)))
+    (cond ((< 0 days)
+           (format "%d-%02d:%02d:%02d" days hours minutes seconds))
+          ((< 0 hours)
+           (format "%02d:%02d:%02d" hours minutes seconds))
+          (t
+           (format "%02d:%02d" minutes seconds)))))
+
+(defun proced-format-start (start)
+  "Format time START.
+The return string is always 6 characters wide."
+  (let ((d-start (decode-time start))
+        (d-current (decode-time)))
+    (cond ( ;; process started in previous years
+           (< (nth 5 d-start) (nth 5 d-current))
+           (format-time-string "  %Y" start))
+          ;; process started today
+          ((and (= (nth 3 d-start) (nth 3 d-current))
+                (= (nth 4 d-start) (nth 4 d-current)))
+           (format-time-string " %H:%M" start))
+          (t ;; process started this year
+           (format-time-string "%b %e" start)))))
+
+(defun proced-format-ttname (ttname)
+  "Format attribute TTNAME, omitting prefix \"/dev/\"."
+  ;; Does this work for all systems?
+  (format "%s" (substring ttname
+                          (if (string-match "\\`/dev/" ttname)
+                              (match-end 0) 0))))
+
+(defun proced-format (process-alist format)
+  "Display PROCESS-ALIST using FORMAT."
+  (if (symbolp format)
+      (setq format (cdr (assq format proced-format-alist))))
+  (insert (make-string (length process-alist) ?\n))
+  (let ((whitespace " ") header-list grammar)
+    ;; Loop over all attributes
+    (while (setq grammar (pop format))
+      (if (symbolp grammar)
+          (setq grammar (assq grammar proced-grammar-alist)))
+      (let* ((key (car grammar))
+             (fun (if (stringp (nth 2 grammar))
+                      `(lambda (arg) (format ,(nth 2 grammar) arg))
+                    (nth 2 grammar)))
+             (whitespace (if format whitespace ""))
+             ;; Text properties:
+             ;; We use the text property `proced-key' to store in each
+             ;; field the corresponding key.
+             ;; Of course, the sort predicate appearing in help-echo
+             ;; is only part of the story.  But it gives the main idea.
+             (hprops `(proced-key ,key mouse-face highlight
+                                  help-echo ,(format proced-header-help-echo
+                                                     (if (nth 5 grammar) "-" "+")
+                                                     (nth 1 grammar))))
+             (fprops `(proced-key ,key mouse-face highlight
+                                  help-echo ,(format proced-field-help-echo
+                                                     (nth 1 grammar)
+                                                     (mapconcat (lambda (s)
+                                                                  (if s "+" "-"))
+                                                                (nth 7 grammar) ""))))
+             value)
+
+        (goto-char (point-min))
+        (cond ( ;; fixed width of output field
+               (numberp (nth 3 grammar))
+               (dolist (process process-alist)
+                 (end-of-line)
+                 (setq value (cdr (assq key (cdr process))))
+                 (insert (if value
+                             (apply 'propertize (funcall fun value) fprops)
+                           (make-string (abs (nth 3 grammar)) ?\s))
+                         whitespace)
+                 (forward-line))
+               (push (format (concat "%" (number-to-string (nth 3 grammar)) "s")
+                             (apply 'propertize (nth 1 grammar) hprops))
+                     header-list))
+
+              ( ;; last field left-justified
+               (and (not format) (eq 'left (nth 3 grammar)))
+               (dolist (process process-alist)
+                 (end-of-line)
+                 (setq value (cdr (assq key (cdr process))))
+                 (if value (insert (apply 'propertize (funcall fun value) fprops)))
+                 (forward-line))
+               (push (apply 'propertize (nth 1 grammar) hprops) header-list))
+
+              (t ;; calculated field width
+               (let ((width (length (nth 1 grammar)))
+                     field-list value)
+                 (dolist (process process-alist)
+                   (setq value (cdr (assq key (cdr process))))
+                   (if value
+                       (setq value (apply 'propertize (funcall fun value) fprops)
+                             width (max width (length value))
+                             field-list (cons value field-list))
+                     (push "" field-list)))
+                 (let ((afmt (concat "%" (if (eq 'left (nth 3 grammar)) "-" "")
+                                     (number-to-string width) "s")))
+                   (push (format afmt (apply 'propertize (nth 1 grammar) hprops))
+                         header-list)
+                   (dolist (value (nreverse field-list))
+                     (end-of-line)
+                     (insert (format afmt value) whitespace)
+                     (forward-line))))))))
+
+    ;; final cleanup
+    (goto-char (point-min))
+    (dolist (process process-alist)
+      ;; We use the text property `proced-pid' to store in each line
+      ;; the corresponding pid
+      (put-text-property (point) (line-end-position) 'proced-pid (car process))
+      (forward-line))
+    ;; Set header line
+    (setq proced-header-line
+          (mapconcat 'identity (nreverse header-list) whitespace))
+    (if (string-match "[ \t]+$" proced-header-line)
+        (setq proced-header-line (substring proced-header-line 0
+                                            (match-beginning 0))))
+    ;; (delete-trailing-whitespace)
+    (goto-char (point-min))
+    (while (re-search-forward "[ \t\r]+$" nil t)
+      (delete-region (match-beginning 0) (match-end 0)))))
 
-(defun proced-update (&optional quiet)
+(defun proced-format-interactive (scheme &optional revert)
+  "Format Proced buffer using SCHEME.
+When called interactively, an empty string means nil, i.e., no formatting.
+With prefix REVERT non-nil revert listing."
+  (interactive
+   (let ((scheme (completing-read "Format: "
+                                  proced-format-alist nil t)))
+     (list (if (string= "" scheme) nil (intern scheme))
+           current-prefix-arg)))
+  (setq proced-format scheme)
+  (proced-update revert))
+
+;; generate listing
+
+(defun proced-process-attributes ()
+  "Return alist of attributes for each system process.
+This alist can be customized via `proced-custom-attributes'."
+  (mapcar (lambda (pid)
+            (let* ((attributes (system-process-attributes pid))
+                   (utime (cdr (assq 'utime attributes)))
+                   (stime (cdr (assq 'stime attributes)))
+                   (cutime (cdr (assq 'cutime attributes)))
+                   (cstime (cdr (assq 'cstime attributes))))
+              (setq attributes
+                    (append (list (cons 'pid pid))
+                            (if (and utime stime)
+                                (list (cons 'time (time-add utime stime))))
+                            (if (and cutime cstime)
+                                (list (cons 'ctime (time-add cutime cstime))))
+                            attributes))
+              (dolist (fun proced-custom-attributes)
+                (push (funcall fun attributes) attributes))
+              (cons pid attributes)))
+          (list-system-processes)))
+
+(defun proced-update (&optional revert quiet)
   "Update the `proced' process information.  Preserves point and marks.
+With prefix REVERT non-nil, revert listing.
 Suppress status information if QUIET is nil."
   ;; This is the main function that generates and updates the process listing.
-  (interactive)
-  (or quiet (message "Updating process information..."))
-  (let* ((command (cadr (assoc proced-command proced-command-alist)))
-         (regexp (concat (proced-skip-regexp) "\\s-+\\([0-9]+\\>\\)"))
-         (old-pos (if (save-excursion
-                        (beginning-of-line)
-                        (looking-at (concat "^[* ]" regexp)))
-                      (cons (match-string-no-properties 1)
-                            (current-column))))
-         buffer-read-only mp-list)
-    (goto-char (point-min))
+  (interactive "P")
+  (setq revert (or revert (not proced-process-alist)))
+  (or quiet (message (if revert "Updating process information..."
+                       "Updating process display...")))
+  ;; If point is on a field, we try to return point to that field.
+  ;; Otherwise we try to return to the same column
+  (let ((old-pos (let ((key (get-text-property (point) 'proced-key)))
+                   (list (proced-pid-at-point) key
+                         (if key
+                             (if (get-text-property (1- (point)) 'proced-key)
+                                 (- (point) (previous-single-property-change
+                                             (point) 'proced-key))
+                               0)
+                           (current-column)))))
+        buffer-read-only mp-list)
     ;; remember marked processes (whatever the mark was)
-    (while (re-search-forward (concat "^\\(\\S-\\)" regexp) nil t)
-      (push (cons (match-string-no-properties 2)
+    (goto-char (point-min))
+    (while (re-search-forward "^\\(\\S-\\)" nil t)
+      (push (cons (save-match-data (proced-pid-at-point))
                   (match-string-no-properties 1)) mp-list))
-    ;; generate new listing
+    (when revert
+      ;; all attributes of all processes
+      (setq proced-process-alist (proced-process-attributes))
+      ;; do not keep undo information
+      (if (consp buffer-undo-list)
+          (setq buffer-undo-list nil)))
+    ;; filtering and sorting
+    (setq proced-process-alist
+          (proced-sort (proced-filter proced-process-alist
+                                      proced-filter) proced-sort))
+    ;; generate listing
     (erase-buffer)
-    (apply 'call-process (car command) nil t nil
-           (append (cdr command) (cdr (assoc proced-sorting-scheme
-                                             proced-sorting-schemes-alist))))
+    (proced-format proced-process-alist proced-format)
     (goto-char (point-min))
     (while (not (eobp))
       (insert "  ")
       (forward-line))
-    ;; (delete-trailing-whitespace)
-    (goto-char (point-min))
-    (while (re-search-forward "[ \t\r]+$" nil t)
-      (delete-region (match-beginning 0) (match-end 0)))
-    (goto-char (point-min))
-    (let ((lep (line-end-position)))
-      (setq proced-header-line (buffer-substring-no-properties (point) lep))
-      (setq proced-header-alist nil)
-      ;; FIXME: handle left/right justification properly
-      (while (re-search-forward "\\([^ \t\n]+\\)[ \t]*\\($\\)?" lep t)
-        (push (list (match-string-no-properties 1)
-                    ;; take the column number starting from zero
-                    (- (match-beginning 0) (point-min))
-                    (or (not (not (match-beginning 2)))
-                        (- (match-end 0) (point-min)))
-                    'left)
-              proced-header-alist)))
-    (let ((temp (regexp-opt (mapcar 'car proced-header-alist) t)))
-      (setq proced-sorting-schemes-re
-            (concat "\\`" temp "\\(," temp "\\)*\\'")))
-    ;; remove header line from ps(1) output
+    (setq proced-header-line (concat "  " proced-header-line))
+    (if revert (set-buffer-modified-p nil))
+    ;; set `goal-column'
+    (let ((grammar (assq proced-goal-attribute proced-grammar-alist)))
+      (setq goal-column ;; set to nil if no match
+            (if (and grammar
+                     (not (zerop (buffer-size)))
+                     (string-match (regexp-quote (nth 1 grammar))
+                                   proced-header-line))
+                (if (nth 3 grammar)
+                    (match-beginning 0)
+                  (match-end 0)))))
+    ;; restore process marks and buffer position (if possible)
     (goto-char (point-min))
-    (delete-region (point)
-                   (save-excursion (forward-line) (point)))
-    (set-buffer-modified-p nil)
-    ;; set `proced-goal-column'
-    (if proced-goal-header-re
-        (let ((hlist proced-header-alist) header)
-          (while (setq header (pop hlist))
-            (if (string-match proced-goal-header-re (car header))
-                (setq proced-goal-column
-                      (if (eq 'left (nth 3 header))
-                          (nth 1 header) (nth 2 header))
-                      hlist nil)))))
-    ;; restore process marks
-    (if mp-list
-        (save-excursion
-          (goto-char (point-min))
-          (let (mark)
-            (while (re-search-forward (concat "^" regexp) nil t)
-              (if (setq mark (assoc (match-string-no-properties 1) mp-list))
-                  (save-excursion
-                    (beginning-of-line)
-                    (insert (cdr mark))
-                    (delete-char 1)))))))
-    ;; restore buffer position (if possible)
-    (goto-char (point-min))
-    (if (and old-pos
-             (re-search-forward
-              (concat "^[* ]" (proced-skip-regexp) "\\s-+" (car old-pos) "\\>")
-              nil t))
-        (progn
-          (beginning-of-line)
-          (forward-char (cdr old-pos)))
+    (if (or mp-list old-pos)
+        (let (pid mark new-pos)
+          (while (not (eobp))
+            (setq pid (proced-pid-at-point))
+            (when (setq mark (assq pid mp-list))
+              (insert (cdr mark))
+              (delete-char 1)
+              (beginning-of-line))
+            (when (eq (car old-pos) pid)
+              (if (nth 1 old-pos)
+                  (let ((limit (line-end-position)) pos)
+                    (while (and (not new-pos)
+                                (setq pos (next-property-change (point) nil limit)))
+                      (goto-char pos)
+                      (when (eq (nth 1 old-pos)
+                                (get-text-property (point) 'proced-key))
+                        (forward-char (min (nth 2 old-pos)
+                                           (- (next-property-change (point))
+                                              (point))))
+                        (setq new-pos (point))))
+                    (unless new-pos
+                      (setq new-pos (if goal-column
+                                        (+ (line-beginning-position) goal-column)
+                                      (line-beginning-position)))))
+                (setq new-pos (min (+ (line-beginning-position) (nth 2 old-pos))
+                                   (line-end-position)))))
+            (forward-line))
+          (if new-pos
+              (goto-char new-pos)
+            (proced-move-to-goal-column)))
       (proced-move-to-goal-column))
     ;; update modeline
     ;; Does the long mode-name clutter the modeline?
-    (setq mode-name (concat "Proced: " proced-command
-                            (if proced-sorting-scheme
-                                (concat " by " proced-sorting-scheme)
-                              "")))
+    (setq mode-name
+          (concat "Proced"
+                  (if proced-filter
+                      (concat ": " (symbol-name proced-filter))
+                    "")
+                  (if proced-sort
+                      (let* ((key (if (listp proced-sort) (car proced-sort)
+                                    proced-sort))
+                             (grammar (assq key proced-grammar-alist)))
+                        (concat " by " (if (nth 5 grammar) "-" "+")
+                                (nth 1 grammar)))
+                    "")))
     (force-mode-line-update)
     ;; done
     (or quiet (input-pending-p)
-        (message "Updating process information...done."))))
+        (message (if revert "Updating process information...done."
+                   "Updating process display...done.")))))
 
 (defun proced-revert (&rest args)
   "Analog of `revert-buffer'."
-  (proced-update))
+  (proced-update t))
 
 ;; I do not want to reinvent the wheel.  Should we rename `dired-pop-to-buffer'
 ;; and move it to window.el so that proced and ibuffer can easily use it, too?
@@ -637,48 +1252,43 @@ If no process is marked, operate on current process.
 SIGNAL may be a string (HUP, INT, TERM, etc.) or a number.
 If SIGNAL is nil display marked processes and query interactively for SIGNAL."
   (interactive)
-  (let ((regexp (concat (proced-marker-regexp)
-                        (proced-skip-regexp) "\\s-+\\([0-9]+\\>\\).*$"))
-        process-list)
+  (let ((regexp (proced-marker-regexp))
+        process-alist)
     ;; collect marked processes
     (save-excursion
       (goto-char (point-min))
       (while (re-search-forward regexp nil t)
-        (push (cons (match-string-no-properties 1)
-                    ;; How much info should we collect here?  Would it be
-                    ;; better to collect only the PID (to avoid ambiguities)
-                    ;; and the command name?
+        (push (cons (proced-pid-at-point)
+                    ;; How much info should we collect here?
                     (substring (match-string-no-properties 0) 2))
-              process-list)))
-    (setq process-list
-          (if process-list
-              (nreverse process-list)
+              process-alist)))
+    (setq process-alist
+          (if process-alist
+              (nreverse process-alist)
             ;; take current process
-            (save-excursion
-              (beginning-of-line)
-              (looking-at (concat "^" (proced-skip-regexp)
-                                  "\\s-+\\([0-9]+\\>\\).*$"))
-              (list (cons (match-string-no-properties 1)
-                          (substring (match-string-no-properties 0) 2))))))
+            (list (cons (proced-pid-at-point)
+                        (buffer-substring-no-properties
+                         (+ 2 (line-beginning-position))
+                         (line-end-position))))))
     (unless signal
       ;; Display marked processes (code taken from `dired-mark-pop-up').
       (let ((bufname  " *Marked Processes*")
-            (header proced-header-line)) ; inherit header line
+            (header-line (substring-no-properties proced-header-line)))
         (with-current-buffer (get-buffer-create bufname)
           (setq truncate-lines t
-                proced-header-line header
+                proced-header-line header-line ; inherit header line
                 header-line-format '(:eval (proced-header-line)))
           (add-hook 'post-command-hook 'force-mode-line-update nil t)
           (erase-buffer)
-          (dolist (process process-list)
+          (dolist (process process-alist)
             (insert "  " (cdr process) "\n"))
           (save-window-excursion
             (dired-pop-to-buffer bufname) ; all we need
             (let* ((completion-ignore-case t)
-                   (pnum (if (= 1 (length process-list))
+                   (pnum (if (= 1 (length process-alist))
                              "1 process"
-                           (format "%d processes" (length process-list))))
-                   ;; The following is an ugly hack. Is there a better way
+                           (format "%d processes" (length process-alist))))
+                   ;; The following is an ugly hack.  Is there a better way
                    ;; to help people like me to remember the signals and
                    ;; their meanings?
                    (tmp (completing-read (concat "Send signal [" pnum
@@ -698,12 +1308,11 @@ If SIGNAL is nil display marked processes and query interactively for SIGNAL."
                               (if (string-match "\\`[0-9]+\\'" signal)
                                   (string-to-number signal)
                                 (make-symbol signal))
-                            signal))) ; number
-              (dolist (process process-list)
+                            signal)))   ; number
+              (dolist (process process-alist)
                 (condition-case err
                     (if (zerop (funcall
-                                proced-signal-function
-                                (string-to-number (car process)) signal))
+                                proced-signal-function (car process) signal))
                         (setq count (1+ count))
                       (proced-log "%s\n" (cdr process))
                       (push (cdr process) failures))
@@ -714,12 +1323,12 @@ If SIGNAL is nil display marked processes and query interactively for SIGNAL."
           ;; use external system call
           (let ((signal (concat "-" (if (numberp signal)
                                         (number-to-string signal) signal))))
-            (dolist (process process-list)
+            (dolist (process process-alist)
               (with-temp-buffer
                 (condition-case err
                     (if (zerop (call-process
                                 proced-signal-function nil t nil
-                                signal (car process)))
+                                signal (number-to-string (car process))))
                         (setq count (1+ count))
                       (proced-log (current-buffer))
                       (proced-log "%s\n" (cdr process))
@@ -729,32 +1338,35 @@ If SIGNAL is nil display marked processes and query interactively for SIGNAL."
                    (proced-log "%s\n" (cdr process))
                    (push (cdr process) failures)))))))
         (if failures
+            ;; Proced error message are not always very precise.
+            ;; Can we issue a useful one-line summary in the
+            ;; message area (using FAILURES) if only one signal failed?
             (proced-log-summary
              signal
              (format "%d of %d signal%s failed"
-                     (length failures) (length process-list)
-                     (if (= 1 (length process-list)) "" "s")))
+                     (length failures) (length process-alist)
+                     (if (= 1 (length process-alist)) "" "s")))
           (proced-success-message "Sent signal to" count)))
       ;; final clean-up
       (run-hooks 'proced-after-send-signal-hook))))
 
-;; just like `dired-why'
+;; similar to `dired-why'
 (defun proced-why ()
   "Pop up a buffer with error log output from Proced.
 A group of errors from a single command ends with a formfeed.
 Thus, use \\[backward-page] to find the beginning of a group of errors."
   (interactive)
   (if (get-buffer proced-log-buffer)
-      (let ((owindow (selected-window))
-            (window (display-buffer (get-buffer proced-log-buffer))))
-        (unwind-protect
-            (progn
-              (select-window window)
-              (goto-char (point-max))
-              (forward-line -1)
-              (backward-page 1)
-              (recenter 0))
-          (select-window owindow)))))
+      (save-selected-window
+        ;; move `proced-log-buffer' to the front of the buffer list
+        (select-window (display-buffer (get-buffer proced-log-buffer)))
+        (setq truncate-lines t)
+        (set-buffer-modified-p nil)
+        (setq buffer-read-only t)
+        (goto-char (point-max))
+        (forward-line -1)
+        (backward-page 1)
+        (recenter 0))))
 
 ;; similar to `dired-log'
 (defun proced-log (log &rest args)
@@ -767,7 +1379,7 @@ and \f (formfeed) at the end."
   (let ((obuf (current-buffer)))
     (with-current-buffer (get-buffer-create proced-log-buffer)
       (goto-char (point-max))
-      (let ((inhibit-read-only t))
+      (let (buffer-read-only)
         (cond ((stringp log)
                (insert (if args
                            (apply 'format log args)
@@ -811,61 +1423,6 @@ buffer.  You can use it to recover marks."
   (message "Change in Proced buffer undone.
 Killed processes cannot be recovered by Emacs."))
 
-;;; Sorting
-(defun proced-sort (scheme)
-  "Sort Proced buffer using SCHEME.
-When called interactively, an empty string means nil, i.e., no sorting."
-  (interactive
-   (list (let* ((completion-ignore-case t)
-                ;; restrict completion list to applicable sorting schemes
-                (completion-list
-                 (apply 'append
-                        (mapcar (lambda (x)
-                                  (if (string-match proced-sorting-schemes-re
-                                                    (car x))
-                                      (list (car x))))
-                                proced-sorting-schemes-alist)))
-                (scheme (completing-read "Sorting type: "
-                                         completion-list nil t)))
-           (if (string= "" scheme) nil scheme))))
-  (if (proced-sorting-scheme-p scheme)
-      (progn
-        (setq proced-sorting-scheme scheme)
-        (proced-update))
-    (error "Proced sorting scheme %s not applicable" scheme)))
-
-(defun proced-sorting-scheme-p (scheme)
-  "Return non-nil if SCHEME is an applicable sorting scheme.
-SCHEME must be a string or nil."
-  (or (not scheme)
-      (and (string-match proced-sorting-schemes-re scheme)
-           (assoc scheme proced-sorting-schemes-alist))))
-
-(defun proced-sort-pcpu ()
-  "Sort Proced buffer by percentage CPU time (%CPU)."
-  (interactive)
-  (proced-sort "%CPU"))
-
-(defun proced-sort-pmem ()
-  "Sort Proced buffer by percentage memory usage (%MEM)."
-  (interactive)
-  (proced-sort "%MEM"))
-
-(defun proced-sort-pid ()
-  "Sort Proced buffer by PID."
-  (interactive)
-  (proced-sort "PID"))
-
-(defun proced-sort-start ()
-  "Sort Proced buffer by time the command started (START)."
-  (interactive)
-  (proced-sort "START"))
-
-(defun proced-sort-time ()
-  "Sort Proced buffer by cumulative CPU time (TIME)."
-  (interactive)
-  (proced-sort "TIME"))
-
 (provide 'proced)
 
 ;; arch-tag: a6e312ad-9032-45aa-972d-31a8cfc545af