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[emacs.git] / lisp / emacs-lisp / ewoc.el
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1 ;;; ewoc.el --- utility to maintain a view of a list of objects in a buffer
3 ;; Copyright (C) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 04
4 ;; Free Software Foundation
6 ;; Author: Per Cederqvist <ceder@lysator.liu.se>
7 ;; Inge Wallin <inge@lysator.liu.se>
8 ;; Maintainer: monnier@gnu.org
9 ;; Created: 3 Aug 1992
10 ;; Keywords: extensions, lisp
12 ;; This file is part of GNU Emacs.
14 ;; GNU Emacs is free software; you can redistribute it and/or modify
15 ;; it under the terms of the GNU General Public License as published by
16 ;; the Free Software Foundation; either version 2, or (at your option)
17 ;; any later version.
19 ;; GNU Emacs is distributed in the hope that it will be useful,
20 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
21 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 ;; GNU General Public License for more details.
24 ;; You should have received a copy of the GNU General Public License
25 ;; along with GNU Emacs; see the file COPYING. If not, write to the
26 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
27 ;; Boston, MA 02111-1307, USA.
29 ;;; Commentary:
31 ;; Ewoc Was Once Cookie
32 ;; But now it's Emacs' Widget for Object Collections
34 ;; As the name implies this derives from the `cookie' package (part
35 ;; of Elib). The changes are pervasive though mostly superficial:
37 ;; - uses CL (and its `defstruct')
38 ;; - separate from Elib.
39 ;; - uses its own version of a doubly-linked list which allows us
40 ;; to merge the elib-wrapper and the elib-node structures into ewoc-node
41 ;; - dropping functions not used by PCL-CVS (the only client of ewoc at the
42 ;; time of writing)
43 ;; - removing unused arguments
44 ;; - renaming:
45 ;; elib-node ==> ewoc--node
46 ;; collection ==> ewoc
47 ;; tin ==> ewoc--node
48 ;; cookie ==> data or element or elem
50 ;; Introduction
51 ;; ============
53 ;; Ewoc is a package that implements a connection between an
54 ;; dll (a doubly linked list) and the contents of a buffer.
55 ;; Possible uses are dired (have all files in a list, and show them),
56 ;; buffer-list, kom-prioritize (in the LysKOM elisp client) and
57 ;; others. pcl-cvs.el uses ewoc.el.
59 ;; Ewoc can be considered as the `view' part of a model-view-controller.
61 ;; A `element' can be any lisp object. When you use the ewoc
62 ;; package you specify a pretty-printer, a function that inserts
63 ;; a printable representation of the element in the buffer. (The
64 ;; pretty-printer should use "insert" and not
65 ;; "insert-before-markers").
67 ;; A `ewoc' consists of a doubly linked list of elements, a
68 ;; header, a footer and a pretty-printer. It is displayed at a
69 ;; certain point in a certain buffer. (The buffer and point are
70 ;; fixed when the ewoc is created). The header and the footer
71 ;; are constant strings. They appear before and after the elements.
73 ;; Ewoc does not affect the mode of the buffer in any way. It
74 ;; merely makes it easy to connect an underlying data representation
75 ;; to the buffer contents.
77 ;; A `ewoc--node' is an object that contains one element. There are
78 ;; functions in this package that given an ewoc--node extract the data, or
79 ;; give the next or previous ewoc--node. (All ewoc--nodes are linked together
80 ;; in a doubly linked list. The `previous' ewoc--node is the one that appears
81 ;; before the other in the buffer.) You should not do anything with
82 ;; an ewoc--node except pass it to the functions in this package.
84 ;; An ewoc is a very dynamic thing. You can easily add or delete elements.
85 ;; You can apply a function to all elements in an ewoc, etc, etc.
87 ;; Remember that an element can be anything. Your imagination is the
88 ;; limit! It is even possible to have another ewoc as an
89 ;; element. In that way some kind of tree hierarchy can be created.
91 ;; Full documentation will, God willing, soon be available in a
92 ;; Texinfo manual.
94 ;; In the mean time `grep '^(.*ewoc-[^-]' emacs-lisp/ewoc.el' can help
95 ;; you find all the exported functions:
97 ;; (defun ewoc-create (pretty-printer &optional header footer)
98 ;; (defalias 'ewoc-data 'ewoc--node-data)
99 ;; (defun ewoc-location (node)
100 ;; (defun ewoc-enter-first (ewoc data)
101 ;; (defun ewoc-enter-last (ewoc data)
102 ;; (defun ewoc-enter-after (ewoc node data)
103 ;; (defun ewoc-enter-before (ewoc node data)
104 ;; (defun ewoc-next (ewoc node)
105 ;; (defun ewoc-prev (ewoc node)
106 ;; (defun ewoc-nth (ewoc n)
107 ;; (defun ewoc-map (map-function ewoc &rest args)
108 ;; (defun ewoc-filter (ewoc predicate &rest args)
109 ;; (defun ewoc-locate (ewoc &optional pos guess)
110 ;; (defun ewoc-invalidate (ewoc &rest nodes)
111 ;; (defun ewoc-goto-prev (ewoc arg)
112 ;; (defun ewoc-goto-next (ewoc arg)
113 ;; (defun ewoc-goto-node (ewoc node)
114 ;; (defun ewoc-refresh (ewoc)
115 ;; (defun ewoc-collect (ewoc predicate &rest args)
116 ;; (defun ewoc-buffer (ewoc)
117 ;; (defun ewoc-get-hf (ewoc)
118 ;; (defun ewoc-set-hf (ewoc header footer)
120 ;; Coding conventions
121 ;; ==================
123 ;; All functions of course start with `ewoc'. Functions and macros
124 ;; starting with the prefix `ewoc--' are meant for internal use,
125 ;; while those starting with `ewoc-' are exported for public use.
126 ;; There are currently no global or buffer-local variables used.
129 ;;; Code:
131 (eval-when-compile (require 'cl)) ;because of CL compiler macros
133 ;; The doubly linked list is implemented as a circular list
134 ;; with a dummy node first and last. The dummy node is used as
135 ;; "the dll" (or rather is the dll handle passed around).
137 (defstruct (ewoc--node
138 (:type vector) ;required for ewoc--node-branch hack
139 (:constructor ewoc--node-create (start-marker data)))
140 left right data start-marker)
142 (defalias 'ewoc--node-branch 'aref
143 "Get the left (CHILD=0) or right (CHILD=1) child of the NODE.
145 \(fn NODE CHILD)")
147 (defun ewoc--dll-create ()
148 "Create an empty doubly linked list."
149 (let ((dummy-node (ewoc--node-create 'DL-LIST 'DL-LIST)))
150 (setf (ewoc--node-right dummy-node) dummy-node)
151 (setf (ewoc--node-left dummy-node) dummy-node)
152 dummy-node))
154 (defun ewoc--node-enter-before (node elemnode)
155 "Insert ELEMNODE before NODE in a DLL."
156 (assert (and (null (ewoc--node-left elemnode)) (null (ewoc--node-right elemnode))))
157 (setf (ewoc--node-left elemnode) (ewoc--node-left node))
158 (setf (ewoc--node-right elemnode) node)
159 (setf (ewoc--node-right (ewoc--node-left node)) elemnode)
160 (setf (ewoc--node-left node) elemnode))
162 (defun ewoc--node-enter-first (dll node)
163 "Add a free floating NODE first in DLL."
164 (ewoc--node-enter-before (ewoc--node-right dll) node))
166 (defun ewoc--node-enter-last (dll node)
167 "Add a free floating NODE last in DLL."
168 (ewoc--node-enter-before dll node))
170 (defun ewoc--node-next (dll node)
171 "Return the node after NODE, or nil if NODE is the last node."
172 (unless (eq (ewoc--node-right node) dll) (ewoc--node-right node)))
174 (defun ewoc--node-prev (dll node)
175 "Return the node before NODE, or nil if NODE is the first node."
176 (unless (eq (ewoc--node-left node) dll) (ewoc--node-left node)))
178 (defun ewoc--node-delete (node)
179 "Unbind NODE from its doubly linked list and return it."
180 ;; This is a no-op when applied to the dummy node. This will return
181 ;; nil if applied to the dummy node since it always contains nil.
182 (setf (ewoc--node-right (ewoc--node-left node)) (ewoc--node-right node))
183 (setf (ewoc--node-left (ewoc--node-right node)) (ewoc--node-left node))
184 (setf (ewoc--node-left node) nil)
185 (setf (ewoc--node-right node) nil)
186 node)
188 (defun ewoc--node-nth (dll n)
189 "Return the Nth node from the doubly linked list DLL.
190 N counts from zero. If DLL is not that long, nil is returned.
191 If N is negative, return the -(N+1)th last element.
192 Thus, (ewoc--node-nth dll 0) returns the first node,
193 and (ewoc--node-nth dll -1) returns the last node."
194 ;; Branch 0 ("follow left pointer") is used when n is negative.
195 ;; Branch 1 ("follow right pointer") is used otherwise.
196 (let* ((branch (if (< n 0) 0 1))
197 (node (ewoc--node-branch dll branch)))
198 (if (< n 0) (setq n (- -1 n)))
199 (while (and (not (eq dll node)) (> n 0))
200 (setq node (ewoc--node-branch node branch))
201 (setq n (1- n)))
202 (unless (eq dll node) node)))
204 (defun ewoc-location (node)
205 "Return the start location of NODE."
206 (ewoc--node-start-marker node))
209 ;;; The ewoc data type
211 (defstruct (ewoc
212 (:constructor nil)
213 (:constructor ewoc--create
214 (buffer pretty-printer header footer dll))
215 (:conc-name ewoc--))
216 buffer pretty-printer header footer dll last-node)
218 (defmacro ewoc--set-buffer-bind-dll-let* (ewoc varlist &rest forms)
219 "Execute FORMS with ewoc--buffer selected as current buffer,
220 dll bound to ewoc--dll, and VARLIST bound as in a let*.
221 dll will be bound when VARLIST is initialized, but the current
222 buffer will *not* have been changed.
223 Return value of last form in FORMS."
224 (let ((old-buffer (make-symbol "old-buffer"))
225 (hnd (make-symbol "ewoc")))
226 `(let* ((,old-buffer (current-buffer))
227 (,hnd ,ewoc)
228 (dll (ewoc--dll ,hnd))
229 ,@varlist)
230 (set-buffer (ewoc--buffer ,hnd))
231 (unwind-protect
232 (progn ,@forms)
233 (set-buffer ,old-buffer)))))
235 (defmacro ewoc--set-buffer-bind-dll (ewoc &rest forms)
236 `(ewoc--set-buffer-bind-dll-let* ,ewoc nil ,@forms))
238 (defsubst ewoc--filter-hf-nodes (ewoc node)
239 "Evaluate NODE once and return it.
240 BUT if it is the header or the footer in EWOC return nil instead."
241 (unless (or (eq node (ewoc--header ewoc))
242 (eq node (ewoc--footer ewoc)))
243 node))
246 (defun ewoc--create-node (data pretty-printer pos)
247 "Call PRETTY-PRINTER with point set at POS in current buffer.
248 Remember the start position. Create a wrapper containing that
249 start position and the element DATA."
250 (save-excursion
251 ;; Remember the position as a number so that it doesn't move
252 ;; when we insert the string.
253 (when (markerp pos) (setq pos (marker-position pos)))
254 (goto-char pos)
255 (let ((inhibit-read-only t))
256 ;; Insert the trailing newline using insert-before-markers
257 ;; so that the start position for the next element is updated.
258 (insert-before-markers ?\n)
259 ;; Move back, and call the pretty-printer.
260 (backward-char 1)
261 (funcall pretty-printer data)
262 (ewoc--node-create (copy-marker pos) data))))
265 (defun ewoc--delete-node-internal (ewoc node)
266 "Delete a data string from EWOC.
267 Can not be used on the footer. Returns the wrapper that is deleted.
268 The start-marker in the wrapper is set to nil, so that it doesn't
269 consume any more resources."
270 (let ((dll (ewoc--dll ewoc))
271 (inhibit-read-only t))
272 ;; If we are about to delete the node pointed at by last-node,
273 ;; set last-node to nil.
274 (if (eq (ewoc--last-node ewoc) node)
275 (setf (ewoc--last-node ewoc) nil))
277 (delete-region (ewoc--node-start-marker node)
278 (ewoc--node-start-marker (ewoc--node-next dll node)))
279 (set-marker (ewoc--node-start-marker node) nil)
280 ;; Delete the node, and return the wrapper.
281 (ewoc--node-delete node)))
284 (defun ewoc--refresh-node (pp node)
285 "Redisplay the element represented by NODE using the pretty-printer PP."
286 (let ((inhibit-read-only t))
287 (save-excursion
288 ;; First, remove the string from the buffer:
289 (delete-region (ewoc--node-start-marker node)
290 (1- (marker-position
291 (ewoc--node-start-marker (ewoc--node-right node)))))
292 ;; Calculate and insert the string.
293 (goto-char (ewoc--node-start-marker node))
294 (funcall pp (ewoc--node-data node)))))
296 ;;; ===========================================================================
297 ;;; Public members of the Ewoc package
300 (defun ewoc-create (pretty-printer &optional header footer)
301 "Create an empty ewoc.
303 The ewoc will be inserted in the current buffer at the current position.
305 PRETTY-PRINTER should be a function that takes one argument, an
306 element, and inserts a string representing it in the buffer (at
307 point). The string PRETTY-PRINTER inserts may be empty or span
308 several lines. A trailing newline will always be inserted
309 automatically. The PRETTY-PRINTER should use `insert', and not
310 `insert-before-markers'.
312 Optional second argument HEADER is a string that will always be
313 present at the top of the ewoc. HEADER should end with a
314 newline. Optional third argument FOOTER is similar, and will
315 be inserted at the bottom of the ewoc."
316 (let ((new-ewoc
317 (ewoc--create (current-buffer)
318 pretty-printer nil nil (ewoc--dll-create)))
319 (pos (point)))
320 (ewoc--set-buffer-bind-dll new-ewoc
321 ;; Set default values
322 (unless header (setq header ""))
323 (unless footer (setq footer ""))
324 (setf (ewoc--node-start-marker dll) (copy-marker pos))
325 (let ((foot (ewoc--create-node footer (lambda (x) (insert footer)) pos))
326 (head (ewoc--create-node header (lambda (x) (insert header)) pos)))
327 (ewoc--node-enter-first dll head)
328 (ewoc--node-enter-last dll foot)
329 (setf (ewoc--header new-ewoc) head)
330 (setf (ewoc--footer new-ewoc) foot)))
331 ;; Return the ewoc
332 new-ewoc))
334 (defalias 'ewoc-data 'ewoc--node-data)
336 (defun ewoc-enter-first (ewoc data)
337 "Enter DATA first in EWOC."
338 (ewoc--set-buffer-bind-dll ewoc
339 (ewoc-enter-after ewoc (ewoc--node-nth dll 0) data)))
341 (defun ewoc-enter-last (ewoc data)
342 "Enter DATA last in EWOC."
343 (ewoc--set-buffer-bind-dll ewoc
344 (ewoc-enter-before ewoc (ewoc--node-nth dll -1) data)))
347 (defun ewoc-enter-after (ewoc node data)
348 "Enter a new element DATA after NODE in EWOC.
349 Returns the new NODE."
350 (ewoc--set-buffer-bind-dll ewoc
351 (ewoc-enter-before ewoc (ewoc--node-next dll node) data)))
353 (defun ewoc-enter-before (ewoc node data)
354 "Enter a new element DATA before NODE in EWOC.
355 Returns the new NODE."
356 (ewoc--set-buffer-bind-dll ewoc
357 (ewoc--node-enter-before
358 node
359 (ewoc--create-node
360 data
361 (ewoc--pretty-printer ewoc)
362 (ewoc--node-start-marker node)))))
364 (defun ewoc-next (ewoc node)
365 "Get the next node.
366 Returns nil if NODE is nil or the last element."
367 (when node
368 (ewoc--filter-hf-nodes
369 ewoc (ewoc--node-next (ewoc--dll ewoc) node))))
371 (defun ewoc-prev (ewoc node)
372 "Get the previous node.
373 Returns nil if NODE is nil or the first element."
374 (when node
375 (ewoc--filter-hf-nodes
376 ewoc
377 (ewoc--node-prev (ewoc--dll ewoc) node))))
380 (defun ewoc-nth (ewoc n)
381 "Return the Nth node.
382 N counts from zero. Return nil if there is less than N elements.
383 If N is negative, return the -(N+1)th last element.
384 Thus, (ewoc-nth dll 0) returns the first node,
385 and (ewoc-nth dll -1) returns the last node.
386 Use `ewoc--node-data' to extract the data from the node."
387 ;; Skip the header (or footer, if n is negative).
388 (setq n (if (< n 0) (1- n) (1+ n)))
389 (ewoc--filter-hf-nodes ewoc
390 (ewoc--node-nth (ewoc--dll ewoc) n)))
392 (defun ewoc-map (map-function ewoc &rest args)
393 "Apply MAP-FUNCTION to all elements in EWOC.
394 MAP-FUNCTION is applied to the first element first.
395 If MAP-FUNCTION returns non-nil the element will be refreshed (its
396 pretty-printer will be called once again).
398 Note that the buffer for EWOC will be the current buffer when
399 MAP-FUNCTION is called. MAP-FUNCTION must restore the current
400 buffer before it returns, if it changes it.
402 If more than two arguments are given, the remaining
403 arguments will be passed to MAP-FUNCTION."
404 (ewoc--set-buffer-bind-dll-let* ewoc
405 ((footer (ewoc--footer ewoc))
406 (node (ewoc--node-nth dll 1)))
407 (while (not (eq node footer))
408 (if (apply map-function (ewoc--node-data node) args)
409 (ewoc--refresh-node (ewoc--pretty-printer ewoc) node))
410 (setq node (ewoc--node-next dll node)))))
412 (defun ewoc-filter (ewoc predicate &rest args)
413 "Remove all elements in EWOC for which PREDICATE returns nil.
414 Note that the buffer for EWOC will be current-buffer when PREDICATE
415 is called. PREDICATE must restore the current buffer before it returns
416 if it changes it.
417 The PREDICATE is called with the element as its first argument. If any
418 ARGS are given they will be passed to the PREDICATE."
419 (ewoc--set-buffer-bind-dll-let* ewoc
420 ((node (ewoc--node-nth dll 1))
421 (footer (ewoc--footer ewoc))
422 (next nil))
423 (while (not (eq node footer))
424 (setq next (ewoc--node-next dll node))
425 (unless (apply predicate (ewoc--node-data node) args)
426 (ewoc--delete-node-internal ewoc node))
427 (setq node next))))
429 (defun ewoc-locate (ewoc &optional pos guess)
430 "Return the node that POS (a buffer position) is within.
431 POS may be a marker or an integer. It defaults to point.
432 GUESS should be a node that it is likely to be near POS.
434 If POS points before the first element, the first node is returned.
435 If POS points after the last element, the last node is returned.
436 If the EWOC is empty, nil is returned."
437 (unless pos (setq pos (point)))
438 (ewoc--set-buffer-bind-dll-let* ewoc
439 ((footer (ewoc--footer ewoc)))
441 (cond
442 ;; Nothing present?
443 ((eq (ewoc--node-nth dll 1) (ewoc--node-nth dll -1))
444 nil)
446 ;; Before second elem?
447 ((< pos (ewoc--node-start-marker (ewoc--node-nth dll 2)))
448 (ewoc--node-nth dll 1))
450 ;; After one-before-last elem?
451 ((>= pos (ewoc--node-start-marker (ewoc--node-nth dll -2)))
452 (ewoc--node-nth dll -2))
454 ;; We now know that pos is within a elem.
456 ;; Make an educated guess about which of the three known
457 ;; node'es (the first, the last, or GUESS) is nearest.
458 (let* ((best-guess (ewoc--node-nth dll 1))
459 (distance (abs (- pos (ewoc--node-start-marker best-guess)))))
460 (when guess
461 (let ((d (abs (- pos (ewoc--node-start-marker guess)))))
462 (when (< d distance)
463 (setq distance d)
464 (setq best-guess guess))))
466 (let* ((g (ewoc--node-nth dll -1)) ;Check the last elem
467 (d (abs (- pos (ewoc--node-start-marker g)))))
468 (when (< d distance)
469 (setq distance d)
470 (setq best-guess g)))
472 (when (ewoc--last-node ewoc) ;Check "previous".
473 (let* ((g (ewoc--last-node ewoc))
474 (d (abs (- pos (ewoc--node-start-marker g)))))
475 (when (< d distance)
476 (setq distance d)
477 (setq best-guess g))))
479 ;; best-guess is now a "best guess".
480 ;; Find the correct node. First determine in which direction
481 ;; it lies, and then move in that direction until it is found.
483 (cond
484 ;; Is pos after the guess?
485 ((>= pos
486 (ewoc--node-start-marker best-guess))
487 ;; Loop until we are exactly one node too far down...
488 (while (>= pos (ewoc--node-start-marker best-guess))
489 (setq best-guess (ewoc--node-next dll best-guess)))
490 ;; ...and return the previous node.
491 (ewoc--node-prev dll best-guess))
493 ;; Pos is before best-guess
495 (while (< pos (ewoc--node-start-marker best-guess))
496 (setq best-guess (ewoc--node-prev dll best-guess)))
497 best-guess)))))))
499 (defun ewoc-invalidate (ewoc &rest nodes)
500 "Refresh some elements.
501 The pretty-printer set for EWOC will be called for all NODES."
502 (ewoc--set-buffer-bind-dll ewoc
503 (dolist (node nodes)
504 (ewoc--refresh-node (ewoc--pretty-printer ewoc) node))))
506 (defun ewoc-goto-prev (ewoc arg)
507 "Move point to the ARGth previous element.
508 Don't move if we are at the first element, or if EWOC is empty.
509 Returns the node we moved to."
510 (ewoc--set-buffer-bind-dll-let* ewoc
511 ((node (ewoc-locate ewoc (point))))
512 (when node
513 ;; If we were past the last element, first jump to it.
514 (when (>= (point) (ewoc--node-start-marker (ewoc--node-right node)))
515 (setq arg (1- arg)))
516 (while (and node (> arg 0))
517 (setq arg (1- arg))
518 (setq node (ewoc--node-prev dll node)))
519 ;; Never step above the first element.
520 (unless (ewoc--filter-hf-nodes ewoc node)
521 (setq node (ewoc--node-nth dll 1)))
522 (ewoc-goto-node ewoc node))))
524 (defun ewoc-goto-next (ewoc arg)
525 "Move point to the ARGth next element.
526 Returns the node (or nil if we just passed the last node)."
527 (ewoc--set-buffer-bind-dll-let* ewoc
528 ((node (ewoc-locate ewoc (point))))
529 (while (and node (> arg 0))
530 (setq arg (1- arg))
531 (setq node (ewoc--node-next dll node)))
532 ;; Never step below the first element.
533 ;; (unless (ewoc--filter-hf-nodes ewoc node)
534 ;; (setq node (ewoc--node-nth dll -2)))
535 (ewoc-goto-node ewoc node)))
537 (defun ewoc-goto-node (ewoc node)
538 "Move point to NODE."
539 (ewoc--set-buffer-bind-dll ewoc
540 (goto-char (ewoc--node-start-marker node))
541 (if goal-column (move-to-column goal-column))
542 (setf (ewoc--last-node ewoc) node)))
544 (defun ewoc-refresh (ewoc)
545 "Refresh all data in EWOC.
546 The pretty-printer that was specified when the EWOC was created
547 will be called for all elements in EWOC.
548 Note that `ewoc-invalidate' is more efficient if only a small
549 number of elements needs to be refreshed."
550 (ewoc--set-buffer-bind-dll-let* ewoc
551 ((footer (ewoc--footer ewoc)))
552 (let ((inhibit-read-only t))
553 (delete-region (ewoc--node-start-marker (ewoc--node-nth dll 1))
554 (ewoc--node-start-marker footer))
555 (goto-char (ewoc--node-start-marker footer))
556 (let ((node (ewoc--node-nth dll 1)))
557 (while (not (eq node footer))
558 (set-marker (ewoc--node-start-marker node) (point))
559 (funcall (ewoc--pretty-printer ewoc)
560 (ewoc--node-data node))
561 (insert "\n")
562 (setq node (ewoc--node-next dll node)))))
563 (set-marker (ewoc--node-start-marker footer) (point))))
565 (defun ewoc-collect (ewoc predicate &rest args)
566 "Select elements from EWOC using PREDICATE.
567 Return a list of all selected data elements.
568 PREDICATE is a function that takes a data element as its first
569 argument. The elements on the returned list will appear in the
570 same order as in the buffer. You should not rely on the order of
571 calls to PREDICATE.
572 Note that the buffer the EWOC is displayed in is the current
573 buffer when PREDICATE is called. PREDICATE must restore it if it
574 changes it.
575 If more than two arguments are given the
576 remaining arguments will be passed to PREDICATE."
577 (ewoc--set-buffer-bind-dll-let* ewoc
578 ((header (ewoc--header ewoc))
579 (node (ewoc--node-nth dll -2))
580 result)
581 (while (not (eq node header))
582 (if (apply predicate (ewoc--node-data node) args)
583 (push (ewoc--node-data node) result))
584 (setq node (ewoc--node-prev dll node)))
585 (nreverse result)))
587 (defun ewoc-buffer (ewoc)
588 "Return the buffer that is associated with EWOC.
589 Returns nil if the buffer has been deleted."
590 (let ((buf (ewoc--buffer ewoc)))
591 (when (buffer-name buf) buf)))
593 (defun ewoc-get-hf (ewoc)
594 "Return a cons cell containing the (HEADER . FOOTER) of EWOC."
595 (cons (ewoc--node-data (ewoc--header ewoc))
596 (ewoc--node-data (ewoc--footer ewoc))))
598 (defun ewoc-set-hf (ewoc header footer)
599 "Set the HEADER and FOOTER of EWOC."
600 (setf (ewoc--node-data (ewoc--header ewoc)) header)
601 (setf (ewoc--node-data (ewoc--footer ewoc)) footer)
602 (ewoc--refresh-node (lambda (x) (insert header)) (ewoc--header ewoc))
603 (ewoc--refresh-node (lambda (x) (insert footer)) (ewoc--footer ewoc)))
606 (provide 'ewoc)
608 ;;; Local Variables:
609 ;;; eval: (put 'ewoc--set-buffer-bind-dll 'lisp-indent-hook 1)
610 ;;; eval: (put 'ewoc--set-buffer-bind-dll-let* 'lisp-indent-hook 2)
611 ;;; End:
613 ;;; arch-tag: d78915b9-9a07-44bf-aac6-04a1fc1bd6d4
614 ;;; ewoc.el ends here