* lisp/emacs-lisp/tabulated-list.el: New file.

etc/NEWS

@@ -691,6 +691,9 @@ consult.
 ** New global minor modes electric-pair-mode, electric-indent-mode,
 and electric-layout-mode.
 
+** tabulated-list.el provides a generic major mode for tabulated data,
+from which other modes can be derived.
+
 ** pcase.el provides the ML-style pattern matching macro `pcase'.
 
 ** secrets.el is an implementation of the Secret Service API, an

lisp/ChangeLog

+2011-04-06  Chong Yidong  <cyd@stupidchicken.com>
+
+	* emacs-lisp/tabulated-list.el: New file.
+
 2011-04-06  Juanma Barranquero  <lekktu@gmail.com>
 
 	* files.el (after-find-file-from-revert-buffer): Remove variable.

lisp/emacs-lisp/tabulated-list.el

+;;; tabulated-list.el --- generic major mode for tabulated lists.
+
+;; Copyright (C) 2011 Free Software Foundation, Inc.
+
+;; Author: Chong Yidong <cyd@stupidchicken.com>
+;; Keywords: extensions, lisp
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 3, or (at your option)
+;; any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; This file defines `tabulated-list-mode', a generic major mode for displaying
+;; lists of tabulated data, intended for other major modes to inherit from.  It
+;; provides several utility routines, e.g. for pretty-printing lines of
+;; tabulated data to fit into the appropriate columns.
+
+;; For usage information, see the documentation of `tabulated-list-mode'.
+
+;; This package originated from Tom Tromey's Package Menu mode, extended and
+;; generalized to be used by other modes.
+
+;;; Code:
+
+(defvar tabulated-list-format nil
+  "The format of the current Tabulated List mode buffer.
+This should be a vector of elements (NAME WIDTH SORT), where:
+ - NAME is a string describing the column.
+ - WIDTH is the width to reserve for the column.
+   For the final element, its numerical value is ignored.
+ - SORT specifies how to sort entries by this column.
+   If nil, this column cannot be used for sorting.
+   If t, sort by comparing the string value printed in the column.
+   Otherwise, it should be a predicate function suitable for
+   `sort', accepting arguments with the same form as the elements
+   of `tabulated-list-entries'.")
+(make-variable-buffer-local 'tabulated-list-format)
+
+(defvar tabulated-list-entries nil
+  "Entries displayed in the current Tabulated List buffer.
+This should be either a function, or a list.
+If a list, each element has the form (ID [DESC1 ... DESCN]),
+where:
+ - ID is nil, or a Lisp object uniquely identifying this entry,
+   which is used to keep the cursor on the \"same\" entry when
+   rearranging the list.  Comparison is done with `equal'.
+
+ - Each DESC is a column descriptor, one for each column
+   specified in `tabulated-list-format'.  A descriptor is either
+   a string, which is printed as-is, or a list (LABEL . PROPS),
+   which means to use `insert-text-button' to insert a text
+   button with label LABEL and button properties PROPS.
+   The string, or button label, must not contain any newline.
+
+If `tabulated-list-entries' is a function, it is called with no
+arguments and must return a list of the above form.")
+(make-variable-buffer-local 'tabulated-list-entries)
+
+(defvar tabulated-list-padding 0
+  "Number of characters preceding each Tabulated List mode entry.
+By default, lines are padded with spaces, but you can use the
+function `tabulated-list-put-tag' to change this.")
+(make-variable-buffer-local 'tabulated-list-padding)
+
+(defvar tabulated-list-revert-hook nil
+  "Hook run before reverting a Tabulated List buffer.
+This is commonly used to recompute `tabulated-list-entries'.")
+
+(defvar tabulated-list-printer 'tabulated-list-print-entry
+  "Function for inserting a Tabulated List entry at point.
+It is called with two arguments, ID and COLS.  ID is a Lisp
+object identifying the entry, and COLS is a vector of column
+descriptors, as documented in `tabulated-list-entries'.")
+(make-variable-buffer-local 'tabulated-list-printer)
+
+(defvar tabulated-list-sort-key nil
+  "Sort key for the current Tabulated List mode buffer.
+If nil, no additional sorting is performed.
+Otherwise, this should be a cons cell (NAME . FLIP).
+NAME is a string matching one of the column names in
+`tabulated-list-format' (the corresponding SORT entry in
+`tabulated-list-format' then specifies how to sort).  FLIP, if
+non-nil, means to invert the resulting sort.")
+(make-variable-buffer-local 'tabulated-list-sort-key)
+
+(defun tabulated-list-get-id (&optional pos)
+  "Obtain the entry ID of the Tabulated List mode entry at POS.
+This is an ID object from `tabulated-list-entries', or nil.
+POS, if omitted or nil, defaults to point."
+  (get-text-property (or pos (point)) 'tabulated-list-id))
+
+(defun tabulated-list-put-tag (tag &optional advance)
+  "Put TAG in the padding area of the current line.
+TAG should be a string, with length <= `tabulated-list-padding'.
+If ADVANCE is non-nil, move forward by one line afterwards."
+  (unless (stringp tag)
+    (error "Invalid argument to `tabulated-list-put-tag'"))
+  (unless (> tabulated-list-padding 0)
+    (error "Unable to tag the current line"))
+  (save-excursion
+    (beginning-of-line)
+    (when (get-text-property (point) 'tabulated-list-id)
+      (let ((beg (point))
+	    (inhibit-read-only t))
+	(forward-char tabulated-list-padding)
+	(insert-and-inherit
+	 (if (<= (length tag) tabulated-list-padding)
+	     (concat tag
+		     (make-string (- tabulated-list-padding (length tag))
+				  ?\s))
+	   (substring tag 0 tabulated-list-padding)))
+	(delete-region beg (+ beg tabulated-list-padding)))))
+  (if advance
+      (forward-line)))
+
+(defvar tabulated-list-mode-map
+  (let ((map (copy-keymap special-mode-map)))
+    (set-keymap-parent map button-buffer-map)
+    (define-key map "n" 'next-line)
+    (define-key map "p" 'previous-line)
+    (define-key map [follow-link] 'mouse-face)
+    (define-key map [mouse-2] 'mouse-select-window)
+    map)
+  "Local keymap for `tabulated-list-mode' buffers.")
+
+(defvar tabulated-list-sort-button-map
+  (let ((map (make-sparse-keymap)))
+    (define-key map [header-line mouse-1] 'tabulated-list-col-sort)
+    (define-key map [header-line mouse-2] 'tabulated-list-col-sort)
+    (define-key map [follow-link] 'mouse-face)
+    map)
+  "Local keymap for `tabulated-list-mode' sort buttons.")
+
+(defun tabulated-list-init-header ()
+  "Set up header line for the Tabulated List buffer."
+  (let ((x tabulated-list-padding)
+	(button-props `(help-echo "Click to sort by column"
+			mouse-face highlight
+			keymap ,tabulated-list-sort-button-map))
+	(cols nil))
+    (if (> tabulated-list-padding 0)
+	(push (propertize " " 'display `(space :align-to ,x)) cols))
+    (dotimes (n (length tabulated-list-format))
+      (let* ((col (aref tabulated-list-format n))
+	     (width (nth 1 col))
+	     (label (car col)))
+	(setq x (+ x 1 width))
+	(and (<= tabulated-list-padding 0)
+	     (= n 0)
+	     (setq label (concat " " label)))
+	(push
+	 (cond
+	  ;; An unsortable column
+	  ((not (nth 2 col)) label)
+	  ;; The selected sort column
+	  ((equal (car col) (car tabulated-list-sort-key))
+	   (apply 'propertize
+		  (concat label
+			  (cond
+			   ((> (+ 2 (length label)) width)
+			    "")
+			   ((cdr tabulated-list-sort-key)
+			    " ▲")
+			   (t " ▼")))
+		  'face 'bold
+		  'tabulated-list-column-name (car col)
+		  button-props))
+	  ;; Unselected sortable column.
+	  (t (apply 'propertize label
+		    'tabulated-list-column-name (car col)
+		    button-props)))
+	 cols))
+      (push (propertize " "
+			'display (list 'space :align-to x)
+			'face 'fixed-pitch)
+	    cols))
+    (setq header-line-format (mapconcat 'identity (nreverse cols) ""))))
+
+(defun tabulated-list-revert (&rest ignored)
+  "The `revert-buffer-function' for `tabulated-list-mode'.
+It runs `tabulated-list-revert-hook', then calls `tabulated-list-print'."
+  (interactive)
+  (unless (derived-mode-p 'tabulated-list-mode)
+    (error "The current buffer is not in Tabulated List mode"))
+  (run-hooks 'tabulated-list-revert-hook)
+  (tabulated-list-print t))
+
+(defun tabulated-list-print (&optional remember-pos)
+  "Populate the current Tabulated List mode buffer.
+This sorts the `tabulated-list-entries' list if sorting is
+specified by `tabulated-list-sort-key'.  It then erases the
+buffer and inserts the entries with `tabulated-list-printer'.
+
+Optional argument REMEMBER-POS, if non-nil, means to move point
+to the entry with the same ID element as the current line."
+  (let ((inhibit-read-only t)
+	(entries (if (functionp 'tabulated-list-entries)
+		     (funcall tabulated-list-entries)
+		   tabulated-list-entries))
+	entry-id saved-pt saved-col)
+    (and remember-pos
+	 (setq entry-id (tabulated-list-get-id))
+	 (setq saved-col (current-column)))
+    (erase-buffer)
+    ;; Sort the buffers, if necessary.
+    (when tabulated-list-sort-key
+      (let ((sort-column (car tabulated-list-sort-key))
+	    (len (length tabulated-list-format))
+	    (n 0)
+	    sorter)
+	;; Which column is to be sorted?
+	(while (and (< n len)
+		    (not (equal (car (aref tabulated-list-format n))
+				sort-column)))
+	  (setq n (1+ n)))
+	(when (< n len)
+	  (setq sorter (nth 2 (aref tabulated-list-format n)))
+	  (when (eq sorter t)
+	    (setq sorter ; Default sorter checks column N:
+		  `(lambda (A B)
+		     (setq A (aref (cadr A) ,n))
+		     (setq B (aref (cadr B) ,n))
+		     (string< (if (stringp A) A (car A))
+			      (if (stringp B) B (car B))))))
+	  (setq entries (sort entries sorter))
+	  (if (cdr tabulated-list-sort-key)
+	      (setq entries (nreverse entries)))
+	  (unless (functionp 'tabulated-list-entries)
+	    (setq tabulated-list-entries entries)))))
+    ;; Print the resulting list.
+    (dolist (elt entries)
+      (and entry-id
+	   (equal entry-id (car elt))
+	   (setq saved-pt (point)))
+      (apply tabulated-list-printer elt))
+    (set-buffer-modified-p nil)
+    ;; If REMEMBER-POS was specified, move to the "old" location.
+    (if saved-pt
+	(progn (goto-char saved-pt)
+	       (move-to-column saved-col))
+      (goto-char (point-min)))))
+
+(defun tabulated-list-print-entry (id cols)
+  "Insert a Tabulated List entry at point.
+This is the default `tabulated-list-printer' function.  ID is a
+Lisp object identifying the entry to print, and COLS is a vector
+of column descriptors."
+  (let ((beg (point))
+	(x (max tabulated-list-padding 0))
+	(len (length tabulated-list-format)))
+    (if (> tabulated-list-padding 0)
+	(insert (make-string x ?\s)))
+    (dotimes (n len)
+      (let* ((format (aref tabulated-list-format n))
+	     (desc   (aref cols n))
+	     (width  (nth 1 format))
+	     (label  (if (stringp desc) desc (car desc)))
+	     (help-echo (concat (car format) ": " label)))
+	;; Truncate labels if necessary.
+	(and (> width 6)
+	     (> (length label) width)
+	     (setq label (concat (substring desc 0 (- width 3))
+				 "...")))
+	(if (stringp desc)
+	    (insert (propertize label 'help-echo help-echo))
+	  (apply 'insert-text-button label (cdr desc)))
+	(setq x (+ x 1 width)))
+      ;; No need to append any spaces if this is the last column.
+      (if (< (1+ n) len)
+	  (indent-to x 1)))
+    (insert ?\n)
+    (put-text-property beg (point) 'tabulated-list-id id)))
+
+(defun tabulated-list-col-sort (&optional e)
+  "Sort Tabulated List entries by the column of the mouse click E."
+  (interactive "e")
+  (let* ((pos (event-start e))
+	 (obj (posn-object pos))
+	 (name (get-text-property (if obj (cdr obj) (posn-point pos))
+				  'tabulated-list-column-name
+				  (car obj))))
+    (with-current-buffer (window-buffer (posn-window pos))
+      (when (derived-mode-p 'tabulated-list-mode)
+	;; Flip the sort order on a second click.
+	(if (equal name (car tabulated-list-sort-key))
+	    (setcdr tabulated-list-sort-key
+		    (not (cdr tabulated-list-sort-key)))
+	  (setq tabulated-list-sort-key (cons name nil)))
+	(tabulated-list-init-header)
+	(tabulated-list-print t)))))
+
+;;; The mode definition:
+
+;;;###autoload
+(define-derived-mode tabulated-list-mode special-mode "Tabulated"
+  "Generic major mode for browsing a list of items.
+This mode is usually not used directly; instead, other major
+modes are derived from it, using `define-derived-mode'.
+
+In this major mode, the buffer is divided into multiple columns,
+which are labelled using the header line.  Each non-empty line
+belongs to one \"entry\", and the entries can be sorted according
+to their column values.
+
+An inheriting mode should usually do the following in their body:
+
+ - Set `tabulated-list-format', specifying the column format.
+ - Set `tabulated-list-revert-hook', if the buffer contents need
+   to be specially recomputed prior to `revert-buffer'.
+ - Maybe set a `tabulated-list-entries' function (see below).
+ - Maybe set `tabulated-list-printer' (see below).
+ - Maybe set `tabulated-list-padding'.
+ - Call `tabulated-list-init-header' to initialize `header-line-format'
+   according to `tabulated-list-format'.
+
+An inheriting mode is usually accompanied by a \"list-FOO\"
+command (e.g. `list-packages', `list-processes').  This command
+creates or switches to a buffer and enables the major mode in
+that buffer.  If `tabulated-list-entries' is not a function, the
+command should initialize it to a list of entries for displaying.
+Finally, it should call `tabulated-list-print'.
+
+`tabulated-list-print' calls the printer function specified by
+`tabulated-list-printer', once for each entry.  The default
+printer is `tabulated-list-print-entry', but a mode that keeps
+data in an ewoc may instead specify a printer function (e.g., one
+that calls `ewoc-enter-last'), with `tabulated-list-print-entry'
+as the ewoc pretty-printer."
+  (setq truncate-lines t)
+  (setq buffer-read-only t)
+  (set (make-local-variable 'revert-buffer-function)
+       'tabulated-list-revert))
+
+(put 'tabulated-list-mode 'mode-class 'special)
+
+(provide 'tabulated-list)
+
+;; Local Variables:
+;; coding: utf-8
+;; lexical-binding: t
+;; End:
+
+;;; tabulated-list.el ends here